第二周周报

前言：

这周真的有点懒，打完比赛基本没补题，最近聚会有点多，希望下周能调整好时间

1第三场比赛

1.CodeForces - 1791C 

0和1作为字符使用时要加单引号

#include<bits/stdc++.h>
#define ll long long
const long long N = 1e9 + 10;
using namespace std;

int main() {
	int t;
	cin >> t;
	while(t--){
		int n;
		cin >> n;
		int cnt = n;
		string s;
		cin >> s;
		if(s.empty()){
			cout << 0 << endl;
		}
		while(s.size() > 1){
			if((s[0] == '0' && s[s.size()-1] == '1') || (s[0] == '1' && s[s.size()-1] == '0')){
				s.erase(s.size()-1,1);//这里的0和1没写单引号
				s.erase(0,1);
				cnt -= 2;
			}else{
				break;
			}
		}
			cout << cnt << endl;
	}
	
	return 0;
}

2.CodeForces - 1791A

暴力即可

#include<bits/stdc++.h>
#define ll long long
const long long N = 1e9 + 10;
using namespace std;

int main() {
	int t;
	cin >> t;
	string s = "codeforces";
	for(int i = 0; i < t; i ++){
		char a;
		cin >> a;
		bool b = false;
		for(int i = 0; i < s.size(); i ++){
			if(a == s[i]){
				b = true;
				break;
			}
		}
		if(b){
			cout << "YES" << endl;
		}else{
			cout << "NO" << endl;
		}
	}
	return 0;
}

3.CodeForces - 1807C 

只有相同的两个字符中间必须间隔为奇数才能输出yes

#include<bits/stdc++.h>
#define ll long long
const long long N = 1e9 + 10;
using namespace std;

int main() {
	int t;
	cin >> t;
	while(t--){
		int n;
		cin >> n;
		string s;
		cin >> s;
		bool res = false;
		for(int i = 0; i < n; i ++){
			bool ok = false;
			for(int j = i + 1; j < n; j ++){
				if(s[i] == s[j]){
					int temp = j - i;
					if(temp % 2 != 0){
						ok = true;
						break;
					}
				}
			}
			if(ok){
				res = true;
				break;
			}
		}
		if(res){
			cout << "NO" << endl;
		}else{
			cout << "YES" << endl;
		}
		
	}
	return 0;
}

 4.CodeForces - 1807B

直接比较奇数个数和偶数个数

#include<bits/stdc++.h>
#define ll long long
const long long N = 1e9 + 10;
using namespace std;

int main() {
	int t;
	cin >> t;
	while(t--){
		int n;
		cin >> n;
		int s = 0;
		int r = 0;
		for(int i = 0; i < n; i ++){
			int b;
			cin >> b;
			if(b % 2 == 0){
				s += b;
			}else{
				r += b;
			}
		}
		if(s > r){
			cout << "YES" << endl;
		}else{
			cout << "NO" << endl;
		}
	}
	return 0;
}

 2.第四场比赛

1.CodeForces - 1873C 

只要把所有范围框定起来即可

#include<bits/stdc++.h>
#define ll long long
const long long N = 1e9 + 10;
using namespace std;


int main() {
	int t;
	cin >> t;
	char a[110][110];
	while(t--){
		int cnt1 = 0;
		int cnt2 = 0;
		int cnt3 = 0;
		int cnt4 = 0;
		int cnt5 = 0;
		for(int i = 1; i <= 10; i ++){
			for(int j = 1; j <= 10; j ++){
				char b;
				cin >> b;
				a[i][j] = b;
				if(a[i][j] == 'X'){
					if(i == 1 || j == 1 || i == 10 || j == 10){
						cnt1 ++;
					}
					if((i == 2 && j > 1 && j < 10) || (i == 9 && j > 1 && j < 10) || 
						(j == 2 && i > 1 && i < 10) || (j == 9 && i > 1 && i < 10)){
						cnt2 ++;
					}
					if((i == 3 && j > 2 && j < 9) || (i == 8 && j > 2 && j < 9) || 
						(j == 3 && i > 2 && i < 9) || (j == 8 && i > 2 && i < 9)){
						cnt3 ++;
					}
					if((i == 4 && j > 3 && j < 8) || (i == 7 && j > 3 && j < 8) || 
						(j == 4 && i > 3 && i < 8) || (j == 7 && i > 3 && i < 8)){
						cnt4 ++;
					}
					if((i == 5 && j > 4 && j < 7) || (i == 6 && j > 4 && j < 7) || 
						(j == 5 && i > 4 && i < 7) || (j == 6 && i > 4 && i < 7)){
						cnt5 ++;
					}
				}
			}
		}
		int res = cnt1 * 1 + cnt2 * 2 + cnt3 * 3 + cnt4 * 4 + cnt5 * 5;
		cout << res << endl;
	}
	return 0;
}

2. CodeForces - 1873D 

一开始以为时双指针，后面发现其实一个就行

#include<bits/stdc++.h>
#define ll long long
const long long N = 1e9 + 10;
using namespace std;


int main() {
	int t;
	cin >> t;
	while(t--){
		int n,k;
		cin >> n >> k;
		string s;
		cin >> s;
		int cnt = 0;
		for(int i = 0; i < n; i ++){
			if(s[i] == 'B'){
				cnt ++;
				i = i + (k - 1);
			}
		}
		cout << cnt << endl;
	}
	return 0;
}

 3.CodeForces - 1873B

数据范围较小，直接暴力

#include<bits/stdc++.h>
#define ll long long
const long long N = 1e9 + 10;
using namespace std;

int max1(vector<ll> &s,int n){
	ll r = 1;
	for(int i = 0; i < n; i ++){
		r *= s[i]; 
	}
	return r;
}

int main() {
	int t;
	cin >> t;
	while(t--){
		int n;
		cin >> n;
		vector<ll>s;
		for(int i = 0; i < n; i ++){
			int a;
			cin >> a;
			s.push_back(a);
		}
		vector<ll>b;
		for(int i = 0; i < n; i ++){
			b.push_back(s[i]);
		}
		ll max = 0;
		for(int i = 0; i < n; i ++){
			s[i] = s[i] + 1;
			ll res = max1(s,n);
			if(res > max){
				max = res;
			}
			s[i] = b[i];
			//cout << res << ' ';
		}
		cout << max << endl;
	}
	return 0;
}