**PAT 1068 万绿丛中一点红 （20 分）

#include <iostream>
#include <vector>
#include <map>
using namespace std;
int m, n, tol;
vector<vector<int>> v;
int dir[8][2] = {{-1, -1}, {-1, 0}, {-1, 1}, {0, 1}, {1, 1}, {1, 0}, {1, -1}, {0, -1}};
bool judge(int i, int j) {
    for (int k = 0; k < 8; k++) {
        int tx = i + dir[k][0];
        int ty = j + dir[k][1];
        if (tx >= 0 && tx < n && ty >= 0 && ty < m && v[i][j] - v[tx][ty] >= 0 - tol && v[i][j] - v[tx][ty] <= tol) return false;
    }
    return true;
}
int main() {
    int cnt = 0, x = 0, y = 0;
    scanf("%d%d%d", &m, &n, &tol);
    v.resize(n, vector<int>(m));
    map<int, int> mapp;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            scanf("%d", &v[i][j]);
            mapp[v[i][j]]++;
        }
    }
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            if (mapp[v[i][j]] == 1 && judge(i, j) == true) {
                cnt++;
                x = i + 1;
                y = j + 1;
            }
        }
    }
    if (cnt == 1)
        printf("(%d, %d): %d", y, x, v[x-1][y-1]);
    else if (cnt == 0)
        printf("Not Exist");
    else
        printf("Not Unique");
    return 0;
}