javascript二分尋找

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/*二分尋找(折半尋找)思路:low和high表示下標，選擇每個數組的中點作為基準，比較基準與key的值，若大於基準，則移動low，反之移動high，等於則返回該值，不存在返回-1遇到的問題：寫成了死迴圈，無傳回值*/var arr = [1,4,5,7,3,9,8];var ff = binarySearch(arr,4);console.log(ff);function binarySearch(arr,key) {    var low = 0;    var high = arr.length-1;        while(low<=high){        var mid =Math.floor( (high+low)/2);        if(arr[mid]==key){        return arr[mid];    }        if (key<arr[mid]) {            high = mid;        }else if(key>arr[mid]){            low = mid;        }else{            return mid;        }    }         return -1;    }

 

javascript二分尋找