代码

int binary_search(const unsigned *line, int ub, unsigned value){
    register int down = 0,up = ub - 1;
    register int estimate = 0;
    while( up - down > 15 ){
        estimate = down + 1ull * (up - down) * (value - line[down]) / (line[up] - line[down]);
        if( line[estimate] == value )return estimate;
        if( line[estimate] < value ) down = estimate + 1;
        else                           up = estimate - 1;
    }
    while( line[down] ^ value ) down ++;
    return down;
}

评测结果