hdu 2031 杨辉三角

题意：显示杨辉三角形。

解法：

组合数学公式：combi(n,m)=combi(n-1,m-1)+combi(n-1,m);

至于为什么有这个公式呢？那就是高中数学的内容啦

   1:  #include<stdlib.h>

   2:  #include<string.h>

   3:  #include<stdio.h>

   4:  #define N 31

   5:  int map[N][N];

   6:  void init(){

   7:      int i,j;

   8:      memset(map,0,sizeof(map));

   9:      map[0][0]=1;

  10:      for(i=1;i<N;i++){

  11:          for(j=1;j<=i;j++){

  12:              map[i][j]=map[i-1][j-1]+map[i-1][j];  //关键代码

  13:          }

  14:      }

  15:  }

  16:  int main(){

  17:      int n,i,j,cnt=0;

  18:      init();

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

  20:          cnt++;

  21:          

  22:          for(i=1;i<=n;i++){

  23:              for(j=1;j<=i;j++){

  24:                  if(j!=1) printf(" ");

  25:                  printf("%d",map[i][j]);

  26:              }

  27:              printf("\n");

  28:          }

  29:          printf("\n");

  30:      }

  31:  }

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