题目：

题解：

int** ans;
int* ansColumnSizes;
int ansSize;int* sequence;
int sequenceSize;int** freq;
int freqSize;void dfs(int pos, int rest) {if (rest == 0) {int* tmp = malloc(sizeof(int) * sequenceSize);memcpy(tmp, sequence, sizeof(int) * sequenceSize);ans[ansSize] = tmp;ansColumnSizes[ansSize++] = sequenceSize;return;}if (pos == freqSize || rest < freq[pos][0]) {return;}dfs(pos + 1, rest);int most = fmin(rest / freq[pos][0], freq[pos][1]);for (int i = 1; i <= most; ++i) {sequence[sequenceSize++] = freq[pos][0];dfs(pos + 1, rest - i * freq[pos][0]);}sequenceSize -= most;
}int comp(const void* a, const void* b) {return *(int*)a - *(int*)b;
}int** combinationSum2(int* candidates, int candidatesSize, int target, int* returnSize, int** returnColumnSizes) {ans = malloc(sizeof(int*) * 2001);ansColumnSizes = malloc(sizeof(int) * 2001);sequence = malloc(sizeof(int) * 2001);freq = malloc(sizeof(int*) * 2001);ansSize = sequenceSize = freqSize = 0;qsort(candidates, candidatesSize, sizeof(int), comp);for (int i = 0; i < candidatesSize; ++i) {if (freqSize == 0 || candidates[i] != freq[freqSize - 1][0]) {freq[freqSize] = malloc(sizeof(int) * 2);freq[freqSize][0] = candidates[i];freq[freqSize++][1] = 1;} else {++freq[freqSize - 1][1];}}dfs(0, target);*returnSize = ansSize;*returnColumnSizes = ansColumnSizes;return ans;
}