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tianqing.liang
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二分搜索
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9 files changed

+401
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9 files changed

+401
-2
lines changed

‎08-QuickSort-More/QuickSort3way.dart‎

Lines changed: 1 addition & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,8 +1,7 @@
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import 'ArrayGenerator.dart';
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import 'dart:math';
3-
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/**
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* 二路快排
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* 三路快排
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*/
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class QuickSort3way {
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_QuickSort3way() {}

‎09-Binary-Search-More/up/ArrayGenerator.dart‎

Lines changed: 21 additions & 0 deletions
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import 'dart:math';
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class ArrayGenerator{
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static List generateOrderedArray(int n){
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List arr = List.filled(n, true);
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for(int i = 0;i<n;i++){
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arr[i] =i;
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}
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return arr;
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}
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static List generateRandomArray(int n,int bound){
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List arr = List.filled(n, true);
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Random random = new Random();
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for(int i = 0; i < n; i ++){
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arr[i] = random.nextInt(bound);
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}
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return arr;
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}
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}

‎09-Binary-Search-More/up/BinarySearchCeil.dart‎

Lines changed: 61 additions & 0 deletions
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import 'ArrayGenerator.dart';
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/**
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* 二分搜索
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*/
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class BinarySearch{
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_BinarySearch(){}
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static int search<T>(List data,T target){
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int left = 0, right = data.length - 1;
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// 在 data[l, r] 的范围中查找 target
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while(left <= right){
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int mid = left + ((right - left) / 2).toInt();
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if(data[mid].compareTo(target) == 0)
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return mid;
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if(data[mid].compareTo(target) < 0)
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left = mid + 1;
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else
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right = mid - 1;
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}
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return -1;
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}
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// > target 的最小值索引
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static int upper<T>(List arr,T target){
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int left = 0,right = arr.length;
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while (left < right){
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int mid = left +((right -left)/2).toInt();
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if(arr[mid].compareTo(target)<=0){
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left = mid +1;
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}else{
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right = mid ;
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}
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}
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return left;
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}
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// > target ，返回最小值索引
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// == target，返回最大索引
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static int ceil<T>(List arr,T target){
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int u = upper(arr, target);
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if(u-1>= 0 && arr[u-1].compareTo(target) == 0){
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return u-1;
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}
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return u;
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}
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}
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void main(){
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// int n = 1000;
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// List arr2 = ArrayGenerator.generateOrderedArray(n);
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// print(BinarySearch.search(arr2, 50));
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var arr =[1,1,3,3,5,5,7,7];
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for(var i = 0;i<=6;i++){
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print(BinarySearch.ceil(arr, i));
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}
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}

‎09-Binary-Search-More/up/BinarySearchFloor.dart‎

Lines changed: 107 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,107 @@
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import 'ArrayGenerator.dart';
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/**
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* 二分搜索
5+
*/
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class BinarySearch {
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_BinarySearch() {}
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static int search<T>(List data, T target) {
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int left = 0, right = data.length - 1;
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// 在 data[l, r] 的范围中查找 target
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while (left <= right) {
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int mid = left + ((right - left) / 2).toInt();
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if (data[mid].compareTo(target) == 0) return mid;
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if (data[mid].compareTo(target) < 0)
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left = mid + 1;
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else
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right = mid - 1;
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}
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return -1;
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}
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// > target 的最小值索引
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static int upper<T>(List arr, T target) {
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int left = 0, right = arr.length;
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while (left < right) {
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int mid = left + ((right - left) / 2).toInt();
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if (arr[mid].compareTo(target) <= 0) {
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left = mid + 1;
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} else {
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right = mid;
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}
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}
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return left;
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}
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// > target ，返回最小值索引
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// == target，返回最大索引
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static int upper_ceil<T>(List arr, T target) {
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int u = upper(arr, target);
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if (u - 1 >= 0 && arr[u - 1].compareTo(target) == 0) {
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return u - 1;
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}
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return u;
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}
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// >= target 的最小值索引
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static int lower_ceil<T>(List data, T target) {
50+
int left = 0, right = data.length;
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// 在 data[l, r] 中寻找解
52+
while (left < right) {
53+
int mid = left + ((right - left) / 2).toInt();
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if (data[mid].compareTo(target) < 0)
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left = mid + 1;
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else
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right = mid;
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}
59+
return left;
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}
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// < target 的最大值索引
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static int lower<T>(List data, T target) {
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int left = -1, right = data.length - 1;
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// 在 data[l, r] 中寻找解
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while (left < right) {
67+
int mid = left + ((right - left + 1) / 2).toInt();
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if (data[mid].compareTo(target) < 0)
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left = mid;
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else
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right = mid - 1;
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}
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return left;
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}
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// < target ，返回最大值索引
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// == target，返回最小索引
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static int lower_floor<T>(List data, T target) {
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int l = lower(data, target);
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if (l + 1 < data.length && data[l + 1].compareTo(target) == 0) return l + 1;
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return l;
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}
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// <= target 最大索引
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static int upper_floor<T>(List data, T target) {
86+
int left = -1, right = data.length - 1;
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// 在 data[l, r] 中寻找解
88+
while (left < right) {
89+
int mid = left + ((right - left + 1) / 2).toInt();
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if (data[mid].compareTo(target) <= 0)
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left= mid;
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else
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right = mid - 1;
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}
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return left;
96+
}
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}
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void main() {
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// int n = 1000;
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// List arr2 = ArrayGenerator.generateOrderedArray(n);
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// print(BinarySearch.search(arr2, 50));
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var arr = [1, 1, 3, 3, 5, 5, 7, 7];
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for (var i = 0; i <= 6; i++) {
105+
print(BinarySearch.lower(arr, i));
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}
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}

‎09-Binary-Search-More/up/BinarySearchLowerCeil.dart‎

Lines changed: 85 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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import 'ArrayGenerator.dart';
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/**
4+
* 二分搜索
5+
*/
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class BinarySearch {
7+
_BinarySearch() {}
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9+
static int search<T>(List data, T target) {
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int left = 0, right = data.length - 1;
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12+
// 在 data[l, r] 的范围中查找 target
13+
while (left <= right) {
14+
int mid = left + ((right - left) / 2).toInt();
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if (data[mid].compareTo(target) == 0) return mid;
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if (data[mid].compareTo(target) < 0)
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left = mid + 1;
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else
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right = mid - 1;
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}
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return -1;
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}
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// > target 的最小值索引
25+
static int upper<T>(List arr, T target) {
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int left = 0, right = arr.length;
27+
while (left < right) {
28+
int mid = left + ((right - left) / 2).toInt();
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if (arr[mid].compareTo(target) <= 0) {
30+
left = mid + 1;
31+
} else {
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right = mid;
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}
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}
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return left;
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}
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// > target ，返回最小值索引
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// == target，返回最大索引
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static int upper_ceil<T>(List arr, T target) {
41+
int u = upper(arr, target);
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if (u - 1 >= 0 && arr[u - 1].compareTo(target) == 0) {
43+
return u - 1;
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}
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return u;
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}
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// >= target 的最小值索引
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static int lower_ceil<T>(List data, T target) {
50+
int left = 0, right = data.length;
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// 在 data[l, r] 中寻找解
52+
while (left < right) {
53+
int mid = left + ((right - left) / 2).toInt();
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if (data[mid].compareTo(target) < 0)
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left = mid + 1;
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else
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right = mid;
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}
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return left;
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}
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// < target 的最大值索引
63+
static int lower<T>(List data, T target) {
64+
int left = -1, right = data.length - 1;
65+
// 在 data[l, r] 中寻找解
66+
while (left < right) {
67+
int mid = left + ((right - left + 1) / 2).toInt();
68+
if (data[mid].compareTo(target) < 0)
69+
left = mid;
70+
else
71+
right = mid - 1;
72+
}
73+
return left;
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}
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}
76+
77+
void main() {
78+
// int n = 1000;
79+
// List arr2 = ArrayGenerator.generateOrderedArray(n);
80+
// print(BinarySearch.search(arr2, 50));
81+
var arr = [1, 1, 3, 3, 5, 5, 7, 7];
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for (var i = 0; i <= 6; i++) {
83+
print(BinarySearch.lower(arr, i));
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}
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}

‎09-Binary-Search-More/up/BinarySearchUp.dart‎

Lines changed: 53 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,53 @@
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import 'ArrayGenerator.dart';
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3+
/**
4+
* 二分搜索
5+
*/
6+
class BinarySearch{
7+
8+
_BinarySearch(){}
9+
10+
static int search<T>(List data,T target){
11+
12+
int left = 0, right = data.length - 1;
13+
14+
// 在 data[l, r] 的范围中查找 target
15+
while(left <= right){
16+
int mid = left + ((right - left) / 2).toInt();
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if(data[mid].compareTo(target) == 0)
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return mid;
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if(data[mid].compareTo(target) < 0)
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left = mid + 1;
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else
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right = mid - 1;
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}
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return -1;
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}
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// > target 的最小值索引
28+
static int upper<T>(List arr,T target){
29+
int left = 0,right = arr.length;
30+
while (left < right){
31+
int mid = left +((right -left)/2).toInt();
32+
if(arr[mid].compareTo(target)<=0){
33+
left = mid +1;
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}else{
35+
right = mid ;
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}
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}
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return left;
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}
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}
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void main(){
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// int n = 1000;
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// List arr2 = ArrayGenerator.generateOrderedArray(n);
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// print(BinarySearch.search(arr2, 50));
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var arr =[1,1,3,3,5,5,7,7];
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for(var i = 0;i<=6;i++){
51+
print(BinarySearch.upper(arr, i));
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}
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}

‎09-Binary-Search/ArrayGenerator.dart‎

Lines changed: 21 additions & 0 deletions
Original file line numberDiff line numberDiff line change
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import 'dart:math';
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3+
class ArrayGenerator{
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5+
static List generateOrderedArray(int n){
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List arr = List.filled(n, true);
7+
for(int i = 0;i<n;i++){
8+
arr[i] =i;
9+
}
10+
return arr;
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}
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13+
static List generateRandomArray(int n,int bound){
14+
List arr = List.filled(n, true);
15+
Random random = new Random();
16+
for(int i = 0; i < n; i ++){
17+
arr[i] = random.nextInt(bound);
18+
}
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return arr;
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}
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}

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