var search = function(nums, target) {
let left = 0, right = nums.length - 1;
while (left <= right) {
const mid = Math.floor((right - left) / 2) + left;//取中值
const num = nums[mid];
if (num === target) {//判断中值是否等于目的值
return mid;
} else if (num > target) {
right = mid - 1;
} else {
left = mid + 1;
}
}
return -1;
};
