代码实现：

方法一：模拟——超时

int maximalSquare(char **matrix, int matrixSize, int *matrixColSize) {int maxSide = 0;if (matrix == NULL || matrixColSize == NULL || matrixSize <= 0 || matrixColSize[0] <= 0) {return 0;}for (int i = 0; i < matrixSize; i++) {for (int j = 0; j < matrixColSize[0]; j++) {if (matrix[i][j] == '1') { // 起点int k = 1;int flag = 1;while (flag) {if (i + k >= matrixSize || j + k >= matrixColSize[0]) {flag = 0;break;}for (int x = i; x <= i + k && x < matrixSize; x++) {for (int y = j; y <= j + k && y < matrixColSize[0]; y++) {if (matrix[x][y] == '0') {flag = 0;break;}}if (!flag) {break;}}if (!flag) {break;}k++;}if (maxSide < k) {maxSide = k;}}}}return maxSide * maxSide;
}

方法二：动态规划

#define max(a, b) ((a) > (b) ? (a) : (b))
#define min(a, b) ((a) > (b) ? (b) : (a))int maximalSquare(char **matrix, int matrixSize, int *matrixColSize) {int maxSide = 0;int dp[matrixSize][matrixColSize[0]];memset(dp, 0, sizeof(dp));for (int i = 0; i < matrixSize; i++) {if (matrix[i][0] == '1') {maxSide = max(maxSide, 1);dp[i][0] = 1;}}for (int j = 0; j < matrixColSize[0]; j++) {if (matrix[0][j] == '1') {maxSide = max(maxSide, 1);dp[0][j] = 1;}}for (int i = 1; i < matrixSize; i++) {for (int j = 1; j < matrixColSize[0]; j++) {if (matrix[i][j] == '1') {dp[i][j] = min((min(dp[i - 1][j], dp[i - 1][j - 1])), dp[i][j - 1]) + 1;}if (maxSide < dp[i][j]) {maxSide = dp[i][j];}}}return maxSide * maxSide;
}