【UVa】Partitioning by Palindromes(dp)
设w[i,j]为i-j能分割成的最少回文串
f[i]为前i个字符能够分成的最少回文串
w[i,j]=1 当w[i+1,j-1]==1 && s[i]==s[j] 或 i==j-1 && s[i]==s[j]
w[i,j]=w[i+1,j-1]+2 当s[i]!=s[j]
然后
f[i]=min{f[j]+w[j+1,i], 0<=j<i}
f[0]=0
题目白书有
#include <cstdio> #include <cstring> #include <cmath> #include <string> #include <iostream> #include <algorithm> #include <queue> #include <set> #include <map> using namespace std; typedef long long ll; #define pii pair<int, int> #define mkpii make_pair<int, int> #define pdi pair<double, int> #define mkpdi make_pair<double, int> #define pli pair<ll, int> #define mkpli make_pair<ll, int> #define rep(i, n) for(int i=0; i<(n); ++i) #define for1(i,a,n) for(int i=(a);i<=(n);++i) #define for2(i,a,n) for(int i=(a);i<(n);++i) #define for3(i,a,n) for(int i=(a);i>=(n);--i) #define for4(i,a,n) for(int i=(a);i>(n);--i) #define CC(i,a) memset(i,a,sizeof(i)) #define read(a) a=getint() #define print(a) printf("%d", a) #define dbg(x) cout << (#x) << " = " << (x) << endl #define error(x) (!(x)?puts("error"):0) #define printarr2(a, b, c) for1(_, 1, b) { for1(__, 1, c) cout << a[_][__]; cout << endl; } #define printarr1(a, b) for1(_, 1, b) cout << a[_] << '\t'; cout << endl inline const int getint() { int r=0, k=1; char c=getchar(); for(; c<'0'||c>'9'; c=getchar()) if(c=='-') k=-1; for(; c>='0'&&c<='9'; c=getchar()) r=r*10+c-'0'; return k*r; } inline const int max(const int &a, const int &b) { return a>b?a:b; } inline const int min(const int &a, const int &b) { return a<b?a:b; } const int N=1005; int n, f[N], w[N][N]; char s[N]; int main() { int cs=getint(); while(cs--) { scanf("%s", s+1); n=strlen(s+1); CC(f, 0x3f); CC(w, 0); f[0]=0; for1(i, 1, n) w[i][i]=1; for1(k, 1, n-1) for1(i, 1, n-k) { int j=i+k; if(k==1 && s[i]==s[j]) w[i][j]=1; else if(k>1 && w[i+1][j-1]==1 && s[i]==s[j]) w[i][j]=1; else w[i][j]=w[i+1][j-1]+2; } for1(i, 1, n) rep(j, i) f[i]=min(f[i], f[j]+w[j+1][i]); printf("%d\n", f[n]); } return 0; }
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