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 > 63 ){
        estimate = down + 1ull * (up - down) * (value - line[down]) / (line[up] - line[down]);
        //if( estimate == down ) ++ estimate ;
        //if( estimate == up   ) -- estimate ;
        if( line[estimate] == value )return estimate;
        if( line[estimate] < value ) down = estimate + 1;
        else                           up = estimate - 1;
        //( line[estimate] < value ? down : up ) = estimate;
    }
    while(1) { if( line[down] == value ) return down; down ++; }
    return 0;
}

评测结果