根据下述⼆分查找法，在排好序的数组 1，3，6，9，17，31，39，52，61，79 中查找数值 31，循环 while (left <= right) 执⾏的次数为？
int binary_search(vector < int > & nums, int target) {
int left = 0;
int right = nums.size() - 1;
while (left <= right) {
int mid = left + (right - left) / 2;
if (nums[mid] == target) {
return mid;
} else if (nums[mid] < target) {
left = mid + 1;
} else {
right = mid - 1;
}
}
return -1; // 如果找不到目标元素，返回-1
}
