Problem: 字符迁移

思路：差分数组

#include <bits/stdc++.h>
using namespace std;
int main()
{
    ios::sync_with_stdio(false);
  int n,q;
  cin>>n>>q;
  vector<int> cf(n+2,0);
  string s;
  cin>>s;
    while(q--){
        int  l,r,k;
        cin>>l>>r>>k;
        cf[l]+=k;
        cf[l]%=26;
        cf[r+1]-=k;
        cf[r+1]%=26;
    }
    int sum = 0;
    for(int i=1;i<=n;i++){
        sum=(sum+cf[i])%26; 
        //+26防止负数,如-2%3=-2,+3调到正数1
        s[i-1] = 'a'+(sum+s[i-1]-'a'+26)%26;
    }
    cout <<s<< endl;
  return 0;
}