Vector存取状态

#include <iostream>
#include <vector>
#include <cstring>
using namespace std;
typedef pair<int, int> pii;
vector<pii> res;
int step;
int a[4][4], backup[4][4];
/*
    “+”  闭合状态（0）   “-”  打开状态（1）  
    目标：全打开状态（1）
*/
void read(){
    char tmp;
    for(int i = 0; i < 4; i ++ ){
        for(int j = 0; j < 4; j ++ ){
            cin >> tmp;
            if(tmp == '+')  a[i][j] = 0;
            else    a[i][j] = 1;
        }
    }
}
void work(int x, int y){
    for(int i = 0; i < 4; i ++ )    backup[x][i] ^= 1;
    for(int i = 0; i < 4; i ++ )    backup[i][y] ^= 1;
    backup[x][y] ^= 1;

}
int main(){
    read();
    step = 17;
    for(int k = 0; k < (1 << 16); k ++ ){
        memcpy(backup, a, sizeof a);
        vector<pii> tmp;
        int cnt = 0;
        //1:需要按下    0:不需要按下
        for(int i = 0; i < 16; i ++ ){
            if(k >> i & 1){
                cnt++;
                work(i/4, i%4);
                tmp.push_back({i/4+1, i%4+1});
            }
        }
        //检验
        bool flag = true;
        for(int i = 0; i < 4; i ++ ){
            for(int j = 0; j < 4; j ++ ){
                if(!backup[i][j])   {flag = false;  break;} 
            }
        }
        if(flag && cnt < step){
            res = tmp;
            step = cnt;
        }
    }
    cout << step << endl;
    for(int i = 0; i < res.size(); i ++ ){
        cout << res[i].first << " " << res[i].second << endl;
    }
    return 0;
}