Palindrome

input/code.cpp: In function 'int main()':
input/code.cpp:19:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0; i<s.size(); ++i){
                          ^
input/code.cpp:24:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=1; i<s.size(); ++i){
                          ^
input/code.cpp:34:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (int i=0; i<s.size(); ++i){
                          ^
input/code.cpp:36:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (i<s.size()-1){
                    ^

#include <iostream>
using namespace std;



int dp[2020][2020];


int main(){
  string s;
  cin >> s;
  
  bool si=0;
  for (int j=s.size()-1; j>=0; --j){
    si=(si || (s[j]==s[0]));
    dp[0][j]=s.size()-j-si;
  }
  si=0;
  for (int i=0; i<s.size(); ++i){
    si=(si || (s[i]==s[s.size()-1]));
    dp[i][s.size()-1]=i+1-si;
  }
  
  for (int i=1; i<s.size(); ++i){
    for (int j=s.size()-2; j>=i; --j){
      if (s[i]==s[j]) dp[i][j]=dp[i-1][j+1];
      else{
	dp[i][j]=min(dp[i-1][j+1]+1, min(dp[i-1][j]+1, dp[i][j+1]+1));
      }
    }
  }
  
  int ans=1222333444;
  for (int i=0; i<s.size(); ++i){
    ans=min(ans, dp[i][i]);
    if (i<s.size()-1){
      ans=min(ans, dp[i][i+1]);
    }
  }
  cout << ans << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED

Test 23

Verdict: ACCEPTED

Test 24

Verdict: ACCEPTED

Test 25

Verdict: ACCEPTED

Test 26

Verdict: ACCEPTED

Test 27

Verdict: ACCEPTED

Test 28

Verdict: ACCEPTED

Test 29

Verdict: ACCEPTED

Test 30

Verdict: ACCEPTED