首页 > ACM题库 > HDU-杭电 > HDU 1030 Delta-wave -数学-[解题报告] C++
2013
11-26

HDU 1030 Delta-wave -数学-[解题报告] C++

Delta-wave

问题描述 :

A triangle field is numbered with successive integers in the way shown on the picture below.

The traveller needs to go from the cell with number M to the cell with number N. The traveller is able to enter the cell through cell edges only, he can not travel from cell to cell through vertices. The number of edges the traveller passes makes the length of the traveller’s route.

Write the program to determine the length of the shortest route connecting cells with numbers N and M.

输入:

Input contains two integer numbers M and N in the range from 1 to 1000000000 separated with space(s).

输出:

Output should contain the length of the shortest route.

样例输入:

6 12

样例输出:

3


求三角形内两点的最短路径,题目见这里,很容易证明最短的路径就是两点在三个方向的距离之和。

 

#include <stdio.h>

#include <math.h>

void main() {

    unsigned int m,n,ai,aj,bi,bj,ak,bk;

    while (scanf("%d%d",&m,&n)!=EOF) {

        ai = sqrt(m-1)+1;

        bi = sqrt(n-1)+1;

        aj = (m-(ai-1)*(ai-1)-1)/2+1;

        bj = (n-(bi-1)*(bi-1)-1)/2+1;

        ak = (ai*ai-m)/2+1;

        bk = (bi*bi-n)/2+1;

        printf("%d/n",abs(ai-bi)+abs(aj-bj)+abs(ak-bk));

    }

}

 


  1. 漂亮。佩服。
    P.S. unsigned 应该去掉。换行符是n 不是/n
    还可以稍微优化一下,
    int main() {
    int m,n,ai,aj,bi,bj,ak,bk;
    while (scanf("%d%d",&m,&n)!=EOF) {
    ai = sqrt(m-1);
    bi = sqrt(n-1);
    aj = (m-ai*ai-1)>>1;
    bj = (n-bi*bi-1)>>1;
    ak = ((ai+1)*(ai+1)-m)>>1;
    bk = ((bi+1)*(bi+1)-n)>>1;
    printf("%dn",abs(ai-bi)+abs(aj-bj)+abs(ak-bk));
    }
    }