【CodeForces - 298C】Parity Game (思維,有坑)
題幹:
You are fishing with polar bears Alice and Bob. While waiting for the fish to bite, the polar bears get bored. They come up with a game. First Alice and Bob each writes a 01-string (strings that only contain character "0" and "1") a and b. Then you try to turn a into b
- Write parity(a) to the end of a. For example, .
- Remove the first character of a. For example, . You cannot perform this operation if a is empty.
You can use as many operations as you want. The problem is, is it possible to turn a
The parity of a 01-string is 1 if there is an odd number of "1"s in the string, and 0 otherwise.
Input
The first line contains the string a and the second line contains the string b (1 ≤ |a|, |b| ≤ 1000). Both strings contain only the characters "0" and "1". Here |x
Output
Print "YES" (without quotes) if it is possible to turn a into b, and "NO" (without quotes) otherwise.
Examples
Input
01011 0110
Output
YES
Input
0011 1110
Output
NO
Note
In the first sample, the steps are as follows: 01011 → 1011 → 011 → 0110
題目大意:
告訴你兩種操作,問你能否將A串變成B串。操作1:刪除第一個字元。操作2:在字串後面添parity(a),這個函式的值為0或1,分別在 串中有偶數個1,奇數個1 時取到。
解題報告:
猜結論的思維題。。。模擬了一下發現真的可以,,。也就是看字串中最多能造出多少個1來。,因為如果1 的數量大於等於b串中1的數量,,就一定能構造出來、、就是忘了如果1的個數為奇數的時候,,我們可以直接在後面新增一個1變成多一個1,
AC程式碼:
#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>
#include<map>
#include<vector>
#include<set>
#include<string>
#include<cmath>
#include<cstring>
#define ll long long
#define pb push_back
#define pm make_pair
#define fi first
#define se second
using namespace std;
const int MAX = 2e6 + 5;
int n,k;
char s[MAX],t[MAX];
int main()
{
scanf("%s",s+1);
scanf("%s",t+1);
int cnt1=0,cnt2=0;
for(int i = 1; i<=strlen(s+1); i++) {
if(s[i] == '1') cnt1++;
}
for(int i = 1; i<=strlen(t+1); i++) {
if(t[i] == '1') cnt2++;
}
if(cnt1&1) cnt1++;
if(cnt1 >= cnt2) puts("YES");
else puts("NO");
return 0 ;
}