重复元素全排列

#include <stdio.h>

int data[4] = {1, 1, 2, 2};

/*数据互换*/
void swap(int data[], int index, int i) {
	int temp = data[index];
	data[index] = data[i];
	data[i] = temp;
}

/*是否已有*/
int isEquals(int data[], int index, int i) {
	int j;
	for (j = index; j < i; j++) {
		if (data[j] == data[i]) return 1;
	}
	return 0;
}

/*递归求解，逐个打头*/
void fullArray(int data[], int index, int tail) {
	if (index == tail) {
		int i;
		for (i = 0; i <= tail; i++) {
			printf("%d", data[i]);
		}
		printf("\n");
	} else {
		int i;
		for (i = index; i <= tail; i++) {
			if (!isEquals(data, index, i)) {
				swap(data, index, i);
				fullArray(data, index+1, tail);
				swap(data, index, i);
			}
		}
	}
}

int main() {
	fullArray(data, 0, 3);
	return 0;
}