数字三角形问题 算法入门经典

#include <stdio.h>
#define maxn 100

int buf[maxn][maxn];
int n;
int d(int i, int j){
int t1, t2;
return i == n ? buf[i][j] : buf[i][j] + (((t1 = d(i+1, j)) > (t2 = d(i+1, j+1))) ? t1 : t2);
}

int main(){
/*5
9
12 15
10 6 8
2 18 9 5
19 7 10 4 16
结果 59*/
int i, j;
scanf("%d", &n);
for(i = 1; i <=n; ++i)
for(j = 1; j <= i; ++j)
scanf("%d", &buf[i][j]);
printf("%d\n", d(1, 1));

return 0;
}

#include <stdio.h>
#include <string.h>
#define maxn 100

int buf[maxn][maxn];
int d[maxn][maxn];
int n;
int dfunc(int i, int j){
if(d[i][j] >= 0)  return d[i][j];
return d[i][j] = buf[i][j] + (i == n ? 0  : dfunc(i+1, j) >  dfunc(i+1, j+1) ? dfunc(i+1, j) : dfunc(i+1, j+1));
}

int main(){
int i, j;
scanf("%d", &n);
for(i = 1; i <= n; ++i)
for(j = 1; j <= i; ++j)
scanf("%d", &buf[i][j]);
memset(d, -1, sizeof(d));
printf("%d\n", dfunc(1, 1));

return 0;
}

#include <stdio.h>
#define maxn 200

int d[maxn][maxn];
int n;
void dfunc(){
int i, j;
for(i = n - 1; i >= 1; --i)
for(j = 1; j <= i; ++j)
d[i][j] += d[i+1][j] > d[i+1][j+1] ? d[i+1][j]:d[i+1][j+1];
}

int main(){
int i, j;
scanf("%d", &n);
for(i = 1; i <= n; ++i)
for(j = 1; j <= i; ++j)
scanf("%d", &d[i][j]);
dfunc();
printf("%d\n", d[1][1]);

return 0;
}