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题意:给出一个长字符串,再给一个短字符串,进行匹配,如果第i个恰好匹配,则 +8,;如果不匹配,可以给长或短字符串添加-,先后匹配,这样-3,
连续的长字符串添加-,需要减去一个4;也可不给添加-,则-5。
析:dp[i][j][0] 表示第一个字符串第 i 个位置,和第二个字符串的第 j 个位置相匹配,dp[i][j][1] 表示第一个字符串第 i 个位置,和第二个字符串的第 j 个位置加_相匹配.
那么怎么转移呢?如果s1[i] == s2[j] 那么 dp[i+1][j+1][0] = Max(dp[i+1][j+1][0], Max(dp[i][j][0], dp[i][j][1])+8);意思就是匹配的加8分,
如果不相等,dp[i+1][j+1][0] = Max(dp[i+1][j+1][0], Max(dp[i][j][0], dp[i][j][1])-5);不匹配,减 5 呗。
dp[i][j+1][1] = Max(dp[i][j+1][1], Max(dp[i][j][0]-7, dp[i][j][1]-3));
dp[i+1][j][1] = Max(dp[i+1][j][1], Max(dp[i][j][0]-7, dp[i][j][1]-3));
同样的意思。注意,这个题说学生的串不过50,但是你开小于100就会WA。。。。真坑啊
代码如下:
#pragma comment(linker, "/STACK:1024000000,1024000000") #include <cstdio> #include <string> #include <cstdlib> #include <cmath> #include <iostream> #include <cstring> #include <set> #include <queue> #include <algorithm> #include <vector> #include <map> #include <cctype> #include <cmath> #include <stack> #define freopenr freopen("in.txt", "r", stdin) #define freopenw freopen("out.txt", "w", stdout) using namespace std; typedef long long LL; typedef pair<int, int> P; const int INF = 0x3f3f3f3f; const double inf = 0x3f3f3f3f3f3f; const double PI = acos(-1.0); const double eps = 1e-8; const int maxn = 1e6 + 5; const int mod = 1e8; const char *mark = "+-*"; const int dr[] = {-1, 0, 1, 0, 1, 1, -1, -1}; const int dc[] = {0, 1, 0, -1, -1, 1, 1, -1}; int n, m; const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; inline int Min(int a, int b){ return a < b ? a : b; } inline int Max(int a, int b){ return a > b ? a : b; } inline LL Min(LL a, LL b){ return a < b ? a : b; } inline LL Max(LL a, LL b){ return a > b ? a : b; } inline bool is_in(int r, int c){ return r >= 0 && r < n && c >= 0 && c < m; } char s1[110], s2[110]; int dp[110][110][2]; int main(){ int T; cin >> T; while(T--){ scanf("%s", s1); scanf("%s", s2); int len1 = strlen(s1); int len2 = strlen(s2); for(int i = 0; i <= len1; ++i) for(int j = 0; j <= len2; ++j) for(int k = 0; k < 2; ++k) dp[i][j][k] = -INF; for(int i = 0; i <= len1; ++i) dp[i][0][0] = 0; for(int i = 0; i < len1; ++i){ for(int j = 0; j < len2; ++j){ if(s1[i] == s2[j]) dp[i+1][j+1][0] = Max(dp[i+1][j+1][0], Max(dp[i][j][0], dp[i][j][1])+8); else dp[i+1][j+1][0] = Max(dp[i+1][j+1][0], Max(dp[i][j][0], dp[i][j][1])-5); dp[i][j+1][1] = Max(dp[i][j+1][1], Max(dp[i][j][0]-7, dp[i][j][1]-3)); dp[i+1][j][1] = Max(dp[i+1][j][1], Max(dp[i][j][0]-7, dp[i][j][1]-3)); } } int ans = -INF; for(int i = 0; i <= len1; ++i) ans = Max(ans, Max(dp[i][len2][0], dp[i][len2][1])); printf("%d\n", ans); } return 0; }
UVaLive 6697 Homework Evaluation (DP)
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原文地址:http://www.cnblogs.com/dwtfukgv/p/5801244.html