学步园

水题不解释，直接贴以前的代码

code

/*
ID: yueqiq
PROG: numtri
LANG: C++
*/
#include <set>
#include <map>
#include <ctime>
#include <queue>
#include <cmath>
#include <stack>
#include <limits>
#include <vector>
#include <bitset>
#include <string>
#include <cstdio>
#include <cstring>
#include <fstream>
#include <string.h>
#include <iostream>
#include <algorithm>
#define Si set<int>
#define LL long long
#define pb push_back
#define PS printf(" ")
#define Vi vector<int>
#define LN printf("\n")
#define lson l,m,rt << 1
#define rson m+1,r,rt<<1|1
#define SD(a) scanf("%d",&a)
#define PD(a) printf("%d",a)
#define SET(a,b) memset(a,b,sizeof(a))
#define FF(i,a) for(int i(0);i<(a);i++)
#define FD(i,a) for(int i(a);i>=(1);i--)
#define FOR(i,a,b) for(int i(a);i<=(b);i++)
#define FOD(i,a,b) for(int i(a);i>=(b);i--)
#define readf freopen("numtri.in","r",stdin)
#define writef freopen("numtri.out","w",stdout)
const int maxn = 1001;
const int INF = 1111;
const int dx[]={0,1,0,-1};
const int dy[]={1,0,-1,0};
const double pi = acos(-1.0);
using namespace std;

int N,a[maxn][maxn],f[maxn][maxn];
int main()
{
    readf;
    writef;
    SD(N);
    FOR(i,1,N) FOR(j,1,i){
        SD(a[i][j]);
    }
    FOR(i,1,N) f[N][i]=a[N][i];
    FOD(i,N-1,1){
        FOR(j,1,i){
            f[i][j]=max(f[i+1][j],f[i+1][j+1])+a[i][j];
        }
    }
    PD(f[1][1]);LN;
    return 0;
}