题解 | 最大正方形

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,maxlen = -1;
    cin>>n;
    vector<vector<int>> nums(n,vector<int>(n,0));
    int r1,r2,r3,r4,r5,r6,r7,r8;
    for(int i=0;i<n;i++){
        for(int j=0;j<n;j++){
            char tmp;
            cin>>tmp;
            if(tmp=='#')nums[i][j]=1;
            if(nums[i][j]==1){
            for(int x=0;x<n;x++){
                for(int y=0;y<n;y++){
                    if(nums[x][y]==1){
                        int x3 = i+(y-j), y3 = j-(x-i);
                        int x4 = x+(y-j), y4 = y-(x-i);
                        if(x3<0||x3>=n||y3<0||y3>=n||x4<0||x4>=n||y4<0||y4>=n)continue;
                        if(nums[x3][y3]==1&&nums[x4][y4]==1){
                            int len = (i-x)*(i-x)+(j-y)*(j-y);
                            if(len>maxlen){
                                maxlen = len;
                                r1 = i;r2 = j;r3 = x;r4 = y;
                                r5 = x3;r6 = y3;r7 = x4;r8 = y4;
                            }
                        }
                    }
                }
            }
        }
    }
    }
    cout<<r1+1<<' '<<r2+1<<endl;
    cout<<r3+1<<' '<<r4+1<<endl;
    cout<<r5+1<<' '<<r6+1<<endl;
    cout<<r7+1<<' '<<r8+1<<endl;
    return 0;
}