CodeForces 711B Chris and Magic Square (暴力，水题)

题意：给定n*n个矩阵，其中只有一个格子是0，让你填上一个数，使得所有的行列的对角线的和都相等。

析：首先n为1，就随便填，然后就是除了0这一行或者这一列，那么一定有其他的行列是完整的，所以，先把其他的算出来，然后再作差就算这个数了，

然后再去验证其他的对不对就好了。除了n为1，其他的都是唯一解应该。或者没有。

代码如下：

#pragma comment(linker, "/STACK:1024000000,1024000000")

#include <cstdio>

#include <string>

#include <cstdlib>

#include <cmath>

#include <iostream>

#include <cstring>

#include <set>

#include <queue>

#include <algorithm>

#include <vector>

#include <map>

#include <cctype>

#include <cmath>

#include <stack>

#include <list>

#include <sstream>

#define frer freopen("in.txt", "r", stdin)

#define frew freopen("out.txt", "w", stdout)

using namespace std;

typedef long long LL;

typedef pair<int, int> P;

const int INF = 0x3f3f3f3f;

const double inf = 0x3f3f3f3f3f3f;

const double PI = acos(-1.0);

const double eps = 1e-8;

const int maxn = 5e2 + 5;

const int mod = 1e9 + 7;

const int dr[] = {-1, 1, 0, 0, 1, 1, -1, -1};

const int dc[] = {0, 0, 1, -1, 1, -1, 1, -1};

const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};

int n, m;

const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

inline int Min(int a, int b){ return a < b ? a : b; }

inline int Max(int a, int b){ return a > b ? a : b; }

inline LL Min(LL a, LL b){ return a < b ? a : b; }

inline LL Max(LL a, LL b){ return a > b ? a : b; }

inline bool is_in(int r, int c){

    return r >= 0 && r < n && c >= 0 && c < m;

}

LL a[maxn][maxn];

int main(){

    while(cin >> n){

        memset(a, 0, sizeof a);

        LL sum1 = 0, sum2 = 0;

        int x, y;

        for(int i = 0; i < n; ++i){

            for(int j = 0; j < n; ++j){

                scanf("%I64d", &a[i][j]);

                a[i][n] += a[i][j];

                a[n][j] += a[i][j];

                if(a[i][j] == 0)  x = i, y = j;

                if(i == j)  sum1 += a[i][j];

                if(i + j == n - 1)  sum2 += a[i][j];

            }

        }

        if(1 == n)  printf("1\n");

        else{

            LL ans = 0;

            for(int i = 0; i < n; ++i){

                if(i != x){

                    ans = a[i][n] - a[x][n];

                    a[x][n] += ans;

                    a[n][y] += ans;

                    if(x == y)  sum1 += ans;

                    if(x + y == n - 1)  sum2 += ans;

                    break;

                }

            }

            bool ok = true;

            if(sum1 != sum2 || ans < 1 || ans > 1e18) ok = false;

            if(!ok){  printf("-1\n"); continue;  }

            for(int i = 0; i < n; ++i){

                if(a[i][n] != sum1 || a[n][i] != sum1){  ok = false; break; }

            }

            if(!ok){  printf("-1\n"); continue;  }

            else cout << ans << endl;

        }

    }

    return 0;

}

巴特西

CodeForces 711B Chris and Magic Square (暴力，水题)

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