Prefix and Suffix

题目描述

Snuke is interested in strings that satisfy the following conditions:

The length of the string is at least N.
The first N characters equal to the string s.
The last N characters equal to the string t.
Find the length of the shortest string that satisfies the conditions.

Constraints
1≤N≤100
The lengths of s and t are both N.
s and t consist of lowercase English letters.

输入

The input is given from Standard Input in the following format:

N
s
t

输出

Print the length of the shortest string that satisfies the conditions.

样例输入

3
abc
cde

样例输出

5

提示

The shortest string is 'abcde'.

#include <bits/stdc++.h>

using namespace std;
int main(){
    ios::sync_with_stdio(false);
    int len;
    string a,b;
    cin>>len;
    cin>>a>>b;
    int i,j,sum=len*2,ans=len*2;
    i=len-1,j=len-1;
    while(j>=0&&i>=0)
    {
        if(a[i]==b[j]){
            i--;
            j--;
            sum--;
        }
        else if(a[i]!=b[j]&&i!=len-1){
            i=len-1;
            sum=len*2;
        }
        else if(a[i]!=b[j]&&i==len-1){
            j--;
            sum=len*2;
        }
    }
    i=len-1,j=len-1;
    swap(a,b);
    while(j>=0&&i>=0)
    {
        if(a[i]==b[j]){
            i--;
            j--;
            ans--;
        }
        else if(a[i]!=b[j]&&i!=len-1){
            i=len-1;
            ans=len*2;
        }
        else if(a[i]!=b[j]&&i==len-1){
            j--;
            ans=len*2;
        }
    }
    cout<<min(ans,sum)<<endl;
}

这道题刚开始就WA了一大片

这个不能天真的以为b接在a后面

还有天天吃小白菜的代码真的太乱了

今天亲自敲了一下