POJ1159 (DP)

Title Link: http://poj.org/problem?id=1159

Palindrome

Time Limit: 3000MS		Memory Limit: 65536K
Total Submissions: 56628		Accepted: 19577

Description

A palindrome is a symmetrical string, which is, a string read identically from the left to the right as well as from the right to left. You-to-write a program which, given a string, determines the minimal number of characters to being inserted into the STR ing in order to obtain a palindrome. 

As an example, by inserting 2 characters, the string "ab3bd" can is transformed into a palindrome ("Dab3bad" or "Adb3bda") . However, inserting fewer than 2 characters does not produce a palindrome. 

Input

Your program was to read from standard input. The first line contains one integer:the length of the input string n, 3 <= n <= 5000. The second line contains one string with length N. The string is formed from uppercase letters from "a" to "Z ', lowercase letters from" a "to" Z ' and digits from ' 0 "to ' 9 '. Uppercase and lowercase letters is to be considered distinct.

Output

Your program is-to-write to standard output. The first line contains one integer and which is the desired minimal number.

Sample Input

5ab3bd

Sample Output

2

Source

#include <iostream> #include <cstdio> #include <cstring> #include <stack> #include <queue > #include <map> #include <set> #include <vector> #include <cmath> #include <algorithm> using namespace std; #define LL long longconst double eps = 1e-6;const double pi = ACOs ( -1.0); const int INF = 0x3f3f3f3f;co NST int MOD = 1000000007;int n;short int Dp[5005][5005];char str[5005];int main () {    cin>>n;    cin>>str;    memset (DP, 0, sizeof (DP));    for (int i=1, i<n; i++)    {for        (int j=i-1; j>=0; j--)        {            if (str[i]! = str[j])                dp[i][j] = min (dp[i -1][J], dp[i][j+1]) +1;            else                dp[i][j] = dp[i-1][j+1];        }    }    cout<<dp[n-1][0]<<endl;    return 0;}

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POJ1159 (DP)