代码

int binary_search(const unsigned *line, int ub, unsigned value){
register int down = 0,up=ub;
register int estimate = 0;
    while(1){
        estimate = down + 
        (unsigned long long)(up - down) *
        (value -line[down]) / (line[up] - line[down]);
        if(estimate == down) ++ estimate ;
        if(estimate == up  ) -- estimate ;
        if(line[estimate] == value)return estimate;
        (line[estimate] < value?down:up) = estimate;
    }
    return 0;
}

评测结果