题意:输入一个字符串,至少插入几个字符可以变成回文串(左右对称的字符串) 分析:f[x][y]代表x与y个字符间至少插入f[x][y]个字符可以变成回文串,可以利用动态规划的思想,求解 状态转化方程: f[x][y]=0  初始化 f[x][y]=f[x+1][y-1]     s[x]==s[y]时 f[x][y]=MIN ( f[x+1][y] , f[x][y-1] )+1    s[x] != s[y]时 代码展示 一开始没有将算的的数据存放到数组中,使得有些数据重复计算好多次,TLE…

POJ 1159 Palindrome(字符串变回文:LCS) id=1159">http://poj.org/problem? id=1159 题意: 给你一个字符串, 问你做少须要在该字符串中插入几个字符能是的它变成一个回文串. 分析: 首先把原字符串和它的逆串进行匹配, 找出最长公共子序列. 那么最长公共子序列的字符串肯定是一个回文串. 所以原串剩下的部分是不构成回文的. 我们仅仅须要加入剩下部分的字符到相应位置, 原串自然就变成了一个回文. 所以本题的解为: n 减去 (原串与逆串…

1.链接地址: http://bailian.openjudge.cn/practice/1159/ http://poj.org/problem?id=1159 2.题目: Palindrome Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 49849   Accepted: 17153 Description A palindrome is a symmetrical string, that is, a strin…

A palindrome is a symmetrical string, that is, a string read identically from left to right as well as from right to left. You are to write a program which, given a string, determines the minimal number of characters to be inserted into the string in…

Palindrome Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 59094   Accepted: 20528 Description A palindrome is a symmetrical string, that is, a string read identically from left to right as well as from right to left. You are to write a…

Palindrome Time Limit: 3000MS   Memory Limit: 65536K Total Submissions: 55018   Accepted: 19024 Description A palindrome is a symmetrical string, that is, a string read identically from left to right as well as from right to left. You are to write a…

题目:http://poj.org/problem?id=1159 #include<iostream> #include<cstring> #include<cstdio> using namespace std; int mmin(int a,int b) { return a>b?b:a; } ][]; int main() { int n,i,j; ]; memset(d,,sizeof(d)); cin>>n; ; i<=n; i++)…

题目链接:http://poj.org/problem?id=1159 题目大意:给定一串字符,添加最少的字符,使之成为回文串. Sample Input 5 Ab3bd Sample Output 2 分析:这道题目之前有做过,就是将原字符串逆序得到另一个字符串,求它们的最长公共子序列,这样就能求得它的可以构成回文的最长字符数,用n减去即为添加最少可使之成为回文的数目. 可恨的是之前一直超内存,看了别人的解题报告,原来定义dp[MAX][MAX]时,不用int型,而是short型,内存只占in…

Description A palindrome is a symmetrical string, that is, a string read identically from left to right as well as from right to left. You are to write a program which, given a string, determines the minimal number of characters to be inserted into t…

题目链接:http://poj.org/problem?id=1159 思路分析:对该问题的最优子结构与最长回文子序列相同.根据最长回文子序列的状态方程稍加改变就可以得到该问题动态方程. 假设字符串为A[0, 1, ..., n],则定义状态dp[i, j]表示字符串A[i, i+1, ..., j]成为回文字符串所需要插入的最少字符数,则当A[i] == A[j+1]时, dp[i,j] = dp[i+1, j-1],否则dp[i, j] = Min(dp[i+1, j], dp[i, j+1…