题目: 给定一个没有重复数字的序列,返回其所有可能的全排列。
易错点:
正确写法: (*returnColumnSizes)[i] = numsSize;
错误写法: *returnColumnSizes[i] = numsSize;
/**
* Return an array of arrays of size *returnSize.
* The sizes of the arrays are returned as *returnColumnSizes array.
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
*/
void find(int index, int* path, int *history, int *nums, int numsSize, int ** result, int* result_size)
{
for (int i = 0; i < numsSize; i++) {
//printf("index:%d %d\n", index, path[index]);
if (index == numsSize) {
result[*result_size] = (int *)malloc(numsSize * sizeof(int));
for (int i = 0; i < numsSize; i++) {
result[*result_size][i] = path[i];
}
*result_size += 1;
return;
}
if(history[i] == 1) continue;
path[index++] = nums[i];
history[i] = 1;
find(index, path, history, nums, numsSize, result, result_size);
history[i] = 0;
index--;
}
}
int** permute(int* nums, int numsSize, int* returnSize, int** returnColumnSizes){
if(!nums || numsSize <= 0) {
*returnSize = 0;
*returnColumnSizes = NULL;
return NULL;
}
int* history = (int *)calloc(numsSize, sizeof(int));
int **ret = (int **) calloc(4096, sizeof(int *));
*returnColumnSizes = (int *)calloc (4096, sizeof(int));
int path[4096];
int size = 0;
find(0, path, history, nums, numsSize, ret, &size);
for (int i = 0; i < size; i++) {
(*returnColumnSizes)[i] = numsSize;
}
*returnSize = size;
return ret;
}
/**
* Return an array of arrays of size *returnSize.
* The sizes of the arrays are returned as *returnColumnSizes array.
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
*/
/**
* Return an array of arrays of size *returnSize.
* The sizes of the arrays are returned as *returnColumnSizes array.
* Note: Both returned array and *columnSizes array must be malloced, assume caller calls free().
*/
void find(int index, int* path, int *history, int *nums, int numsSize, int ** result, int* result_size)
{
printf("index:%d %d\n", index, path[index]);
if (index == numsSize) {
result[*result_size] = (int *)malloc(numsSize * sizeof(int));
for (int i = 0; i < numsSize; i++) {
result[*result_size][i] = path[i];
printf("%d ", path[i]);
}
printf("\n");
*result_size += 1;
return;
}
for (int i = 0; i < numsSize; i++) {
if(history[i] == 1 || (i > 0 && nums[i] == nums[i - 1] && history[i - 1] == 0)) {
continue;
}
path[index++] = nums[i];
history[i] = 1;
find(index, path, history, nums, numsSize, result, result_size);
history[i] = 0;
index--;
}
}
int cmp(const void *a, const void *b)
{
return *((int *)a) - *((int *)b);
}
int** permuteUnique(int* nums, int numsSize, int* returnSize, int** returnColumnSizes){
if(!nums || numsSize <= 0) {
*returnSize = 0;
*returnColumnSizes = NULL;
return NULL;
}
qsort(nums, numsSize, sizeof(int), cmp);
int* history = (int *)calloc(numsSize, sizeof(int));
int **ret = (int **) calloc(4096, sizeof(int *));
*returnColumnSizes = (int *)calloc (4096, sizeof(int));
int path[4096];
int size = 0;
find(0, path, history, nums, numsSize, ret, &size);
for (int i = 0; i < size; i++) {
(*returnColumnSizes)[i] = numsSize;
}
*returnSize = size;
return ret;
}