binary search

binarySearch.java

int i = 0, j = n-1;
while(i <= j) {
    int m = i + (j-i) / 2;
    if(arr[m] == target) {
        return m;
    } else if(arr[m] < target) {
        i = m+1;
    } else {
        j = m-1;
    }
}