目录
题目1： P1216 [USACO1.5] [IOI1994]数字三角形 Number Triangles
代码示例：
题目2： Common Subsequence
代码示例
题目3 ：最长上升子序列
最长不下降子序列
最长上升子序列oj答案
题目1： P1216 [USACO1.5] [IOI1994]数字三角形 Number Triangles
P1216 [USACO1.5] [IOI1994]数字三角形 Number Triangles - 洛谷 | 计算机科学教育新生态 (luogu.com.cn)
https://www.luogu.com.cn/problem/P1216
代码示例：
// c++ 代码示例
#include <algorithm>
#include <iostream>using namespace std ;int n,a[1005][1005],f[1005][1005] ;int dfs(int x, int y)
{if (x == n) return a[x][y] ;if (f[x][y] != -1) return f[x][y] ;return f[x][y] = max(dfs(x + 1, y), dfs(x + 1, y + 1)) + a[x][y] ;
}int main()
{int n ;cin >> n ;for (int i = 1 ; i <= n ; i++){for (int j = 1 ; j <= i ; j++){cin >> a[i][j] ;}}for (int i = 1 ; i <= n ; i++){for (int j = 1 ; j <= i ; j++){f[i][j] = -1 ;}}cout << dfs(1, 1) ;return 0 ;
}// c++ 代码示例#include <algorithm>
#include <iostream>
using namespace std ;long long n, a[1005][1005] ;
int main()
{cin >> n ;for (int i = 1 ; i <= n ; i++){for (int j = 1 ; j <= i ; j++){cin >> a[i][j] ;}}for (int i = n ; i >= 1 ; i--){for (int j = 1 ; j <= i ; j++){a[i][j] = a[i][j] + max(a[i + 1][j], a[i + 1][j + 1]); }}cout << a[1][1] ;return 0 ;}
// c++ 代码示例#include <algorithm>
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <cstdio>
#include <string>
using namespace std;#define rint register int
inline void read(int &x)
{x = 0;int w = 1;char ch = getchar();while (!isdigit(ch) && ch != '-'){ch = getchar();}if (ch == '-'){w = -1;ch = getchar();}while (isdigit(ch)){x = (x << 3) + (x << 1) + (ch ^ '0');ch = getchar();}x = x * w;
}const int maxn = 1000 + 10;int n, a[maxn][maxn], ans;int main()
{read(n);for (rint i = 1; i <= n; i++){for (rint j = 1; j <= i; j++){read(a[i][j]);if (i == 1 && j == 1){// The top of the trianglecontinue;}if (j == 1){// Left boundarya[i][j] += a[i - 1][j];}else if (j == i){// Right boundarya[i][j] += a[i - 1][j - 1];}else{// Middle elementsa[i][j] += max(a[i - 1][j - 1], a[i - 1][j]);}ans = max(ans, a[i][j]);}}cout << ans << endl;return 0;
}
题目2： Common Subsequence
Common Subsequence - HDU 1159 - Virtual Judge (vjudge.net)https://vjudge.net/problem/HDU-1159
代码示例
// c++ 代码示例
int a[MAXN], b[MAXN], f[MAXN][MAXN] ;int dp()
{for (int i = 1 ; i <= n ; i++){for (int j = 1 ; j <= m ; j++){if (a[i - 1] == b[j - 1]){f[i][j] = f[i - 1][j - 1] + 1 ;}else{f[i][j] = std::max(f[i - 1][j], f[i][j - 1]) ;}}}return f[n][m] ;
}// c++ 代码示例#include <cmath>
#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <algorithm>using namespace std;char a[1001], b[1001];
int dp[1001][1001], len1, len2;void lcs(int i,int j)
{for(i=1; i<=len1; i++){for(j=1; j<=len2; j++){if(a[i-1] == b[j-1])dp[i][j] = dp[i-1][j-1] + 1;else if(dp[i-1][j] > dp[i][j-1])dp[i][j] = dp[i-1][j];elsedp[i][j] = dp[i][j-1];}}
}int main()
{while(~scanf(" %s",a)){scanf(" %s", b);memset(dp, 0, sizeof(dp));len1 = strlen(a);len2 = strlen(b);lcs(len1, len2);printf("%d\n", dp[len1][len2]);}return 0;
}题目3 ：最长上升子序列
信息学奥赛一本通（C++版）在线评测系统 (ssoier.cn)http://ybt.ssoier.cn:8088/problem_show.php?pid=1281
最长不下降子序列
//c++代码示例
# include <iostream>
# include <cstdio>
using namespace std ;
int n ;
int a[1001] ;
int f[1001] ;
int mx = -1 ;
int main()
{scanf("%d", &n) ;for (int i = 1 ; i <= n ; i++){scanf("%d", &a[i]) ;f[i] = 1 ;}for (int i = 2 ; i <= n ; i++){for (int j = i - 1 ; j >= 1 ; j--){if (a[i] >= a[j]){f[i] = max(f[i], f[j] + 1) ;}}}for (int i = 1 ; i <= n ; i++){mx = max(mx, f[i]) ;}printf("%d", mx) ;return 0 ;}//c++代码示例
# include <iostream>
# include <cstdio>
using namespace std ;
int n ;
int a[1001] ;
int f[1001] ;
int mx = -1 ;
int main()
{scanf("%d", &n) ;for (int i = 1 ; i <= n ; i++){scanf("%d", &a[i]) ;f[i] = 1 ;}for (int i = n - 1 ; i >= 1 ; i--){for (int j = i + 1 ; j <= n ; j++){if (a[i] <= a[j]){f[i] = max(f[i], f[j] + 1) ;}}}for (int i = 1 ; i <= n ; i++){mx = max(mx, f[i]) ;}printf("%d", mx) ;return 0 ;}最长上升子序列oj答案
//c++代码示例
# include <iostream>
# include <cstdio>
using namespace std ;
int n ;
int a[1001] ;
int f[1001] ;
int mx = -1 ;
int main()
{scanf("%d", &n) ;for (int i = 1 ; i <= n ; i++){scanf("%d", &a[i]) ;f[i] = 1 ;}for (int i = n - 1 ; i >= 1 ; i--){for (int j = i + 1 ; j <= n ; j++){if (a[i] < a[j]){f[i] = max(f[i], f[j] + 1) ;}}}for (int i = 1 ; i <= n ; i++){mx = max(mx, f[i]) ;}printf("%d", mx) ;return 0 ;}
