B. Game with string
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output

Two people are playing a game with a string s

, consisting of lowercase latin letters.

On a player‘s turn, he should choose two consecutive equal letters in the string and delete them.
 


For example, if the string is equal to "xaax" than there is only one possible turn: delete "aa", so the string will become "xx". A player not able to make a turn loses.

Your task is to determine which player will win if both play optimally.
Input

The only line contains the string s
, consisting of lowercase latin letters (
 
1≤|s|≤100000), where |s| means the length of a string s

.
Output

If the first player wins, print "Yes". If the second player wins, print "No".

開始用字符串模擬判斷刪除的整個過程，結果各種分類討論，各種出錯

而用string裏自帶的 erase刪除字符 瞬間簡潔

ps：c++ string的erase刪除方法

1. 從位置pos=10處開始刪除，直到結尾 str.erase(10);

2. 刪除叠代器[first, last)區間的所有字符,返回一個指向被刪除的最後一個元素的下一個字符的叠代器. str.erase(str.begin()+10);

string.size() 不能判斷空字符串 刪除字符前要用len保存字符長度

#include<cstdio>
#include<cstring>
#include<iostream>
#include<string>
using namespace std;
 int main(){
     string s;
     int k=0;
     getline(cin,s);
     int len=s.size();
     for(int i=0;i<len;i++){
         while(i>=0&&s[i]==s[i+1]){
//             printf("%d %d %c %c\n",i,i+1,s[i],s[i+1]);
             k++;
             s.erase(s.begin()+i,s.begin()+i+2);
             len-=2;
              if(len<=1)break;
             i--;
            if(i<0)i=0;
//             printf("%d %d %c %c\n",i,i+1,s[i],s[i+1]);
         }
         if(len<=1)break;
     }
     if(k%2==0)printf("No");
     else printf("Yes");
     return 0;
 }

1.23 div2 b-字符串處理(string 與 char 字符串