Codeforces Round #397 by Kaspersky Lab and Barcelona Bootcamp (Div. 1 + Div. 2 combined)-优快云博客

本文链接：https://blog.youkuaiyun.com/sasuke__/article/details/60324617

本文提供了三道算法竞赛题目的解答思路及代码实现：A题利用欧拉回路判断；B题通过模拟解决字符串处理问题；C题则关注特定条件下的数学运算。

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欧拉回路即可

#include <cstdio>
#include <cmath>
#include <cstring>
#include <cctype>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;
#define qq 1e5 + 10
#define REP(i, x, n)	for(int i = x; i < n; ++i)
#define pb push_back
#define mk make_pair
#define LL long long
map<string, int> mp;
int main(){
	int n;	cin >> n;
	string hom, con;
	string st;
	cin >> hom;
	REP(i, 0, n){
		cin >> st;
		hom = st.substr(0, st.find('-'));
		con = st.substr(st.find('>') + 1);
		mp[hom]++;
		mp[con]++;
	}
	map<string, int>:: iterator it;
	bool flag = true;
	for(it = mp.begin(); it != mp.end(); ++it)
		if((it->second % 2) == 1)	flag = false;
	if(flag)	puts("home");
	else	puts("contest");
	return 0;
}

按题意模拟

#include <cstdio>
#include <cmath>
#include <cstring>
#include <cctype>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;
#define qq 1e5 + 10
#define REP(i, x, n)	for(int i = x; i < n; ++i)
#define pb push_back
#define mk make_pair
#define LL long long
int num[30];
char st[1005];
int vis[1005];
int main(){
	scanf("%s", st);
	char ch = 'a';
	bool flag = true;
	REP(i, 0, (int)strlen(st)){
		if(vis[i])	continue;
		if(st[i] != ch){
			flag = false;
			break;
		}
		REP(j, i, (int)strlen(st)){
			if(st[i] == st[j])	vis[j] = 1;
		}
		ch++;
	}
	if(flag)	puts("YES");
	else	puts("NO");
	return 0;
}

就是考虑不成立的情况

#include <cstdio>
#include <cmath>
#include <cstring>
#include <cctype>
#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <utility>
#include <vector>

using namespace std;
#define qq 1e5 + 10
#define REP(i, x, n)	for(int i = x; i < n; ++i)
#define pb push_back
#define mk make_pair
#define LL long long

int main(){
	int k, a, b;	scanf("%d%d%d", &k, &a, &b);
	int sum = a / k + b / k;
	if(a / k == 0){
		if(b % k != 0 || b == 0)	printf("-1\n");
		else	printf("%d\n", sum);
	}else if(b / k == 0){
		if(a % k != 0 || a == 0)	printf("-1\n");
		else	printf("%d\n", sum);
	}else{
		printf("%d\n", sum);
	}
	return 0;
}