题目:
题解:
int* vis;void backtrack(int* nums, int numSize, int** ans, int* ansSize, int idx, int* perm) {if (idx == numSize) {int* tmp = malloc(sizeof(int) * numSize);memcpy(tmp, perm, sizeof(int) * numSize);ans[(*ansSize)++] = tmp;return;}for (int i = 0; i < numSize; ++i) {if (vis[i] || (i > 0 && nums[i] == nums[i - 1] && !vis[i - 1])) {continue;}perm[idx] = nums[i];vis[i] = 1;backtrack(nums, numSize, ans, ansSize, idx + 1, perm);vis[i] = 0;}
}int cmp(void* a, void* b) {return *(int*)a - *(int*)b;
}int** permuteUnique(int* nums, int numsSize, int* returnSize, int** returnColumnSizes) {int** ans = malloc(sizeof(int*) * 2001);int* perm = malloc(sizeof(int) * 2001);vis = malloc(sizeof(int) * numsSize);memset(vis, 0, sizeof(int) * numsSize);qsort(nums, numsSize, sizeof(int), cmp);*returnSize = 0;backtrack(nums, numsSize, ans, returnSize, 0, perm);*returnColumnSizes = malloc(sizeof(int) * (*returnSize));for (int i = 0; i < *returnSize; i++) {(*returnColumnSizes)[i] = numsSize;}return ans;
}