USACO 2017 January Contest, Silver Problem 2. Hoof, Paper, Scissors

原题下载

USACO2017-JAN-S2

答案:

import java.io.*;
import java.util.*;
public class hps {
public static void main(String[] args) throws IOException {
BufferedReader br = new BufferedReader(new FileReader("hps.in"));
PrintWriter pw = new PrintWriter(new BufferedWriter(new FileWriter("hps.out")));
int n = Integer.parseInt(br.readLine());
int[] l = new int[n];
int[] lReverse = new int[n];
for(int i = 0; i < n; i++) {
String s = br.readLine();
if(s.equals("P")) l[i] = 1;
else if(s.equals("S")) l[i] = 2;
lReverse[l.length-1-i] = l[i];
}
int[][] matchPrefix = getMatch(l);
int[][] matchSuffix = getMatch(lReverse);

int ret = 0;
for(int a = 0; a <= n; a++) {
for(int i = 0; i < 3; i++) {
for(int j = 0; j < 3; j++) {
ret = Math.max(ret, matchPrefix[i][a] + matchSuffix[j][n-a]);
}
}
}

pw.println(ret);
pw.close();
}

public static int[][] getMatch(int[] l) {
int[][] matches = new int[3][l.length+1];
for(int i = 0; i < l.length; i++) {
for(int j = 0; j < 3; j++) {
matches[j][i+1] = matches[j][i];
}
matches[l[i]][i+1]++;
}
return matches;
}

}