4-sum问题

给定一个整数数组，判断能否从中找出4个数a、b、c、d，使得他们的和为0，如果能，请找出所有满足和为0个4个数对。

#define SIZE 10
void judgeAndPut(int* arr, int fix1, int fix2, int begin, int end) {
	while (begin < end) {
		int sum = arr[begin] + arr[end] + arr[fix1] + arr[fix2];
		if (sum > 0) {
			end--;
		} else if (sum < 0) {
			begin++;
		} else {
			cout << " " << arr[fix1] << " " << arr[fix2] << " " << arr[begin]
					<< " " << arr[end] << endl;
			begin++;
			end--;
			while (begin + 1 < end && arr[begin + 1] == arr[begin]) {
				begin++;
			}
			while (end - 1 > begin && arr[end - 1] == arr[end]) {
				end--;
			}
		}
	}
}
 
void findFourSumEq0(int* arr) {
	qsort(arr, SIZE, sizeof(int), myCmp);
 
	for (int i = 0; i < SIZE; i++) {
		cout << " " << arr[i];
	}
	cout << endl;
	for (int i = 0; i < SIZE - 3; ++i) {
		if (i != 0 && arr[i] == arr[i - 1]) {
			continue;
		}
		for (int j = i + 1; j < SIZE - 2; ++j) {
			if (j != 1 && arr[j] == arr[j - 1]) {
				continue;
			}
			judgeAndPut(arr, i, j, j + 1, SIZE - 1);
		}
	}
}