Codeforces Round 862 (Div. 2)

Codeforces Round 862 (Div. 2)

链接

Codeforces Round 862 (Div. 2)

A题

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <vector>
#include <cstring>
#include <unordered_set>
#include <set>
#include <stack>
#include <map>
#include <cmath>
#include <sstream>
#include <queue>
#define int long long
#define yes cout<<"YES"<<'\n'
#define no 	cout<<"NO"<<'\n'

using namespace std;
const int N = 1004;

void solve() {
	int n;
	scanf("%lld", &n);
	int a[N];
	for (int i = 1; i <= n; i++) {
		scanf("%lld", &a[i]);
	}
	//对a[1]到a[n]求出最后的异或值
	int v = a[1];
	for (int i = 2; i <= n; i++) {
		v = a[i] ^ v;
	}
	if (v == 0) {//如果异或值为0的话,无论n是多少最后的异或值都为0
		cout << 0 << '\n';
		return;

	}
	if (n % 2 == 0) {//n为偶数相当于再对这个数异或偶数次最后肯定不为0
		cout << -1 << '\n';
	} else {
		cout << v << '\n';//n为奇数相等于再对这个数异或奇数次最后为0

	}



}
signed main () {
	int t;
	cin >> t;
	while (t) {
		solve();
		t--;
	}


	return 0;
}

B题

将最后一个最小的字符串保存起来放到最前面就可以实现这个效果

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>
#include <vector>
#include <cstring>
#include <unordered_set>
#include <set>
#include <stack>
#include <map>
#include <cmath>
#include <sstream>
#include <queue>
#define int long long
#define yes cout<<"YES"<<'\n'
#define no 	cout<<"NO"<<'\n'

using namespace std;
const int N = 100008;

void solve() {
	int n;
	scanf("%lld", &n);
	string s;
	cin >> s;
	int id = 0;
	int mmin = 200;
	for (int i = 0; i < (int)s.size(); i++) {
		if (s[i] <= mmin) {
			mmin = (int)s[i];
			id = i;
		}
	}
	//求存最小的字符和字符所在的位置id
	cout << s[id];//打印这个字符
	for (int i = 0; i < (int)s.size(); i++) {
		if (i == id) {//打印的时候跳过这个字符
			continue;
		} else {
			cout << s[i];//其他整除打印
		}
	}
	cout << '\n';



}


signed main () {
	int t;
	cin >> t;
	while (t) {
		solve();
		t--;
	}


	return 0;
}