循环有序数组找最小值

循环有序数组找最小值

int JudgeAscendingOrDescending(int* data, int len) {
	if (len < 4) {//无法判断
		return -1;
	}
	int flag1=0, flag2=0;
	for (int i = 0; i < 3; i++) {
		if (data[i] > data[i + 1])
			flag1++;
		else
			flag2++;
	}
	if (data[3] > data[0])
		flag1++;
	else
		flag2++;
	if ((flag1 == 4 && flag2 == 0) || (flag1 == 3 && flag2 == 1)) {//降序
		return 1;
	}
	else if ((flag1 == 0 && flag2 == 4) || (flag1 == 1 && flag2 == 3)) {//升序
		return 0;
	}
	else
		return -1;
}
int FindMinValueOfLoopArray(int* data, int len) {
	int mode=JudgeAscendingOrDescending(data,len);
	int l = 0;
	int r = len-1;
	if (mode == 0) {
		if (data[l] < data[r]) {
			return data[l];
		}
		while (l < r) {
			int mid = (l + r) / 2;
			if (data[mid] > data[r]) {
				l = mid + 1;
			}
			else {
				r = mid;
			}
		}
		return data[l];
	}
	else {
		if (data[r] < data[l]) {
			return data[r];
		}
		while (l < r) {
			int mid = (l + r) / 2;
			if (data[mid] < data[r]) {
				l = mid + 1;
			}
			else {
				r = mid;
			}
		}
		return data[l];
	}
}