Add solutions to exercises from competitive programming book (3rd Edition)

UVA/10375.cpp

@@ -0,0 +1,42 @@
+// AC
+#include <bits/stdc++.h>
+using namespace std;
+
+void add_to_queue(priority_queue<int> & q, int val){
+	while(val>1){
+		q.push(val--);
+	}
+}
+
+int main(){
+    #ifndef ONLINE_JUDGE
+       freopen("in.txt","r",stdin);
+    #endif
+	int p, q, r, s;
+	while(cin>>p>>q>>r>>s){
+		priority_queue<int> num;
+		priority_queue<int> den;
+		add_to_queue(num, p);
+		add_to_queue(num, r-s);
+		add_to_queue(num, s);
+		add_to_queue(den, q);
+		add_to_queue(den, p-q);
+		add_to_queue(den, r);
+		long double ans = 1;
+		while (!num.empty() || !den.empty()){
+			if (!num.empty())
+			{
+				ans *= num.top();
+				num.pop();
+			}
+
+			if (!den.empty())
+			{
+				ans /= den.top();
+				den.pop();
+			}
+		}
+		printf("%0.5Lf\n", ans);
+	}
+}
+

UVA/10911.cpp

@@ -0,0 +1,60 @@
+// AC
+// Bitmask dp
+#include <bits/stdc++.h>
+#define INF 1000000000
+using namespace std;
+const int max_size = 1<<16;
+long double dp[max_size];
+bool solved[max_size];
+
+int x[16], y[16], N;
+
+bool done(int mask){
+	return mask == ((1<<2*N)-1);
+}
+
+bool free(int mask, int index){
+	return ((mask>>index) &1) ==0;
+}
+
+long double distance(int a, int b){
+	return sqrt((x[a]-x[b])*(x[a]-x[b]) + (y[a]-y[b])*(y[a]-y[b]));
+}
+
+long double solve(int mask=0){
+	if(solved[mask])
+		return dp[mask];
+	if(done(mask)){
+		solved[mask] = 1;
+		return dp[mask] = 0;
+	}
+	solved[mask] = 1;
+	int first_free = 0;
+	while(!free(mask, first_free)){
+		first_free++;
+	}
+	long double ans = INF;
+	for(int i=first_free+1; i<2*N;i++){
+		if(free(mask, i)){
+			ans = min(ans,
+				distance(first_free, i) + solve(mask | (1<<first_free) | (1<<i)));
+		}
+	}
+	return dp[mask] = ans;
+}
+
+int main(){
+	cin>>N;
+	int t=1;
+	string _;
+
+	while(N){
+		memset(solved, 0, sizeof solved);
+		for(int i=0; i<2*N;i++){
+			cin>>_>>x[i]>>y[i];
+		}
+		printf("Case %d: %0.2LF\n", t, solve());
+		t++;
+		cin>>N;
+	}
+}

UVA/12439.cpp

@@ -0,0 +1,39 @@
+/* AC
+   Inclusion-Exclusion
+   Skip a year if February has already passed
+*/
+
+#include <bits/stdc++.h>
+using namespace std;
+
+int find_no_of_leap(int year){
+	// leap years from 0 to year inclusive
+	return year/4 - year/100 + year/400;
+}
+
+int find_no_of_leap_in_range(int start_year, int end_year){
+	return start_year>end_year?0:find_no_of_leap(end_year) - find_no_of_leap(start_year-1);
+}
+
+int main(){
+	int T;
+	cin>>T;
+	char month[12];
+	int day, start_year, end_year;
+	for(int t=1; t<=T;t++){
+		scanf("%s %d, %d", month, &day, &start_year);
+		string m(month);
+		if (m!="January" && m!="February"){
+			// this year isn't included (February 29 have already passed if it's a leap year)
+			start_year++;
+		}
+		scanf("%s %d, %d", month, &day, &end_year);
+		m = string(month);
+		if (m=="January" || (m=="February" && day<29)){
+			// this year isn't included
+			end_year--;
+		}
+		printf("Case %d: %d\n", t, find_no_of_leap_in_range(start_year, end_year));
+	}
+	return 0;
+}

UVA/573.cpp

@@ -0,0 +1,43 @@
+// AC
+// Lots of tricky statement conditions
+
+#include <bits/stdc++.h>
+#define EPS (1e-10)
+using namespace std;
+
+int main(){
+	int H;
+
+	// Use double for U
+	long double U, D, F;
+	cin>>H>>U>>D>>F;
+	while(H!=0){
+		long double lost_value = U * (0.01*F);
+		long double height = 0;
+		int day = 1;
+		while(true){
+			height += U;
+			// Trick: Snail can reach the top before night (before going down again)
+			if (height > H){
+				// Success
+				printf("success on day %d\n", day);
+				break;
+			}
+			height -= D;
+			// Trick: Avoid double comparison
+			if (height<0 && abs(height)>EPS)
+				break;
+			U -= lost_value;
+
+			// Trick: Snail can't climb negative values
+			if (U<0)
+				U = 0;
+			day++;
+		}
+		if (height<H){
+			// Failure
+			printf("failure on day %d\n", day);
+		}
+		cin>>H>>U>>D>>F;
+	}
+}

UVA/608.cpp

@@ -0,0 +1,108 @@
+/* AC
+
+Hints:
+- If the balance shows even, then all the coins are good
+- If the balance shows up or down, then all the (missing) coins are good.
+"The bad coin is already on the balance, all the other coins are good"
+- Brute force on all the feasible solutions (coins that aren't known to be good)
+and validate the rules.
+*/
+#include <bits/stdc++.h>
+using namespace std;
+string left_s[3], right_s[3], result[3];
+map<char, bool> coins;
+#define EPS (1e-9)
+
+bool in_str(char c, string s){
+	for(int i=0; i< s.size(); i++)
+	{
+		if(c==s[i])
+			return 1;
+	}
+	return 0;
+}
+
+string find_missing(string a, string b){
+	string missing = "";
+	for(char c='A'; c<='L'; c++){
+		if(in_str(c, a) || in_str(c, b))
+			continue;
+		missing += string(c, 1);
+	}
+	return missing;
+}
+
+long double get_weight(string s, char c, bool up){
+	long double weight = 0;
+	for(auto i:s){
+		if(c==i){
+			if(up)
+				// Give the bad coin higher weight
+				weight += 1.5;
+			else
+				// Give the bad coin lower weight
+				weight += 0.5;
+		}
+		else{
+			// The default weight of the coin
+			weight += 1;
+		}
+	}
+	return weight;
+}
+
+bool validate(string l, string r, string res, char c, bool up){
+	long double lw = get_weight(l, c, up);
+	long double rw = get_weight(r, c, up);
+	if (abs(lw-rw)<EPS){
+		return res == "even";
+	}
+	if(lw>rw){
+		return res == "up";
+	}
+	return res == "down";
+}
+
+int main(){
+	int n;
+	cin>>n;
+	while(n--){
+		coins.clear();
+		for(int i=0;i<3;i++){
+			cin>>left_s[i]>>right_s[i]>>result[i];
+			string equal;
+			if (result[i] == "even"){
+				equal = left_s[i] + right_s[i];
+			}
+			else{
+				equal = find_missing(left_s[i], right_s[i]);
+			}
+			for(auto c: equal)
+			{
+				coins[c] = 1;
+			}
+		}
+
+		for(char c='A'; c<='L'; c++){
+			if(coins[c])
+				continue;
+			for(int up=0;up<2;up++){
+				int valid_rules = 0;
+				for(int i=0; i<3; i++){
+					if(validate(left_s[i], right_s[i], result[i], c, up))
+						valid_rules++;
+				}
+				if(valid_rules == 3){
+					// Done
+					printf("%c is the counterfeit coin and it is ", c);
+					if(up)
+						printf("heavy.\n");
+					else
+						printf("light.\n");
+					c = 'M';
+					break;
+				}
+			}
+		}
+	}
+}

UVA/900.cpp

@@ -0,0 +1,24 @@
+// AC
+#include <bits/stdc++.h>
+
+using namespace std;
+long long int dp[51];
+
+long long int solve(int len){
+	if (len<0)
+		return 0;
+	if (len==0)
+		return 1;
+	if (dp[len] != 0)
+		return dp[len];
+	return dp[len] = solve(len-1) + solve(len-2);
+}
+int main(){
+	freopen("in.txt", "r", stdin);
+	int n;
+	cin>>n;
+	while(n!=0){
+		cout<<solve(n)<<endl;
+		cin>>n;
+	}
+}