Submission #98325

#	Time	Username	Problem	Language	Result	Execution time	Memory
98325		rosi	Miners (IOI07_miners)	C++14	100 / 100	32 ms	896 KiB

miners

#include <bits/stdc++.h> 

using namespace std; 
const int MAX_N = 100005; 
const int inf = -1; 
int dp[2][4][4][4]; 
int shipment[MAX_N];
char s[MAX_N]; 
int n; 

int goat(int a, int b, int c) {
  int ret = 0; 
  if (a == 1 || b == 1 || c == 1) {
    ret++;
  }
  if (a == 2 || b == 2 || c == 2) {
    ret++;
  }
  if (a == 3 || b == 3 || c == 3) {
    ret++;
  }
  return ret; 
}

void Max(int &a, int b) {
  a = max(a, b); 
}

void dynamicProgramming() {
  for (int a = 0; a <= 3; a++) {
    for (int b = 0; b <= 3; b++) {
      for (int c = 0; c <= 3; c++) {
        dp[0][a][b][c] = inf; 
      }
    }
  }  
  dp[0][0][0][0] = 0; 
  int res = 0; 
  for (int i = 0; i <= n; i++) {
    int cur = i & 1; 
    int nxt = !cur; 
    for (int a = 0; a <= 3; a++) {
      for (int b = 0; b <= 3; b++) {
        for (int c = 0; c <= 3; c++) {
          dp[nxt][a][b][c] = inf; 
        }
      }
    }
    for (int a = 0; a <= 3; a++) {
      for (int b = 0; b <= 3; b++) {
        for (int c = 0; c <= 3; c++) {
          if (dp[cur][a][b][c] == inf) {
            continue; 
          }
          int val = dp[cur][a][b][c]; 
          res = max(res, val); 
          Max(dp[nxt][shipment[i]][b][c], val + goat(a, shipment[i], shipment[i + 1])); 
          Max(dp[nxt][c][a][shipment[i]], val + goat(b, c, shipment[i + 1])); 
        }
      }
    }
  }
  printf("%d", res); 
}

int main () {
  //freopen("input.txt", "r", stdin);
  //freopen("output.txt", "w", stdout);
  scanf("%d", &n); 
  scanf("%s", s); 
  for (int i = 1; i <= n; i++) {
    if (s[i - 1] == 'M') {
      shipment[i] = 1; 
    }
    else if (s[i - 1] == 'F') {
      shipment[i] = 2; 
    }
    else {
      shipment[i] = 3; 
    }
  }
  dynamicProgramming(); 
  return 0; 
}

Compilation message (stderr)

miners.cpp: In function 'int main()':
miners.cpp:69:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &n); 
   ~~~~~^~~~~~~~~~
miners.cpp:70:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%s", s); 
   ~~~~~^~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 7 / 7
• Subtask 7: 8 / 8
• Subtask 8: 8 / 8
• Subtask 9: 8 / 8
• Subtask 10: 8 / 8
• Subtask 11: 8 / 8
• Subtask 12: 8 / 8