Submission #64394

#	Time	Username	Problem	Language	Result	Execution time	Memory
64394		Just_Solve_The_Problem	parentrises (BOI18_parentrises)	C++11	100 / 100	163 ms	13408 KiB

parentrises

#include <bits/stdc++.h>

using namespace std;

#define pb push_back
#define sz(s) (int)s.size()
#define all(s) s.begin(), s.end()

const int N = (int)1e6 + 7;
const int inf = (int)1e9 + 7;

int b[N];
vector < int > stk;
int a[N];
int mod = (int)1e9 + 7;

bool solve1(string &s) {
  a[0] = 1;
  b[0] = ((s[0] == '(') ? 1 : -1);
  for (int i = 1; i < sz(s); i++) {
    b[i] = b[i - 1] + ((s[i] == '(') ? 1 : -1);
    a[i] = 1;
  }
  int cur = 0;
  stk.clear();
  for (int i = 0; i < sz(s); i++) {
    if (s[i] == ')') stk.pb(i);
    if (b[i] + cur < 0) {
//        cout << i << ' ' << b[i] + cur << ' ' << sz(stk) << endl;
      while (b[i] + cur < 0 && sz(stk) > 1) {
        a[stk.back()] = 0;
        stk.pop_back();
        a[stk.back()] = 2;
        stk.pop_back();
        cur++;
      }
      if (b[i] + cur < 0) {
        return 0;
      }
    }
  }
  cur = 0;
  stk.clear();
  for (int i = 0; i < sz(s); i++) {
    s[i] = ((s[i] == '(') ? ')' : '(');
  }
  reverse(all(s));
  b[0] = ((s[0] == '(') ? 1 : -1);
  for (int i = 1; i < sz(s); i++) {
    b[i] = b[i - 1] + ((s[i] == '(') ? 1 : -1);
  }
  for (int i = 0; i < sz(s); i++) {
    if (a[sz(s) - i - 1] == 2) continue;
    if (s[i] == ')') stk.pb(i);
    if (b[i] + cur < 0) {
//        cout << i << ' ' << b[i] + cur << ' ' << sz(stk) << endl;
      while (b[i] + cur < 0 && sz(stk) > 1) {
        a[sz(s) - stk.back() - 1] = 0;
        stk.pop_back();
        a[sz(s) - stk.back() - 1] = 2;
        stk.pop_back();
        cur++;
      }
      if (b[i] + cur < 0) {
        return 0;
      }
    }
  }
  stk.clear();
  reverse(all(s));
  for (int i = 0; i < sz(s); i++) {
    s[i] = ((s[i] == '(') ? ')' : '(');
  }
  int b1 = 0;
  int b2 = 0;
  bool fl = 0;
  for (int i = 0; i < sz(s); i++) {
    if (a[i] <= 1) {
      b1 += ((s[i] == '(') ? 1 : -1);
    }
    if (a[i] >= 1) {
      b2 += ((s[i] == '(') ? 1 : -1);
    }
    fl |= (b1 < 0 || b2 < 0);
  }
  fl |= (b1 != 0 || b2 != 0);
  if (fl) {
    return 0;
  }
  return 1;
}


int n;

int add(int a, int b) {
  return (a + b) % mod;
}

int dp[2][303][303];
int ans[303];

void solve2() {
  dp[1][0][0] = 1;
  for (int i = 0; i <= 300; i++) {
    for (int j = 0; j <= i; j++) {
      for (int k = 0; k <= j; k++) {
        if (j * 2 < i - j) dp[1][j][k] = 0;
        dp[0][j][k] = dp[1][j][k];
        if (k == 0) ans[i] = add(ans[i], dp[0][j][k]);
      }
    }
    memset(dp[1], 0, sizeof dp[1]);
    for (int j = 0; j <= i; j++) {
      for (int k = 0; k <= j; k++) {
        dp[1][j + 1][k + 1] = add(dp[1][j + 1][k + 1], dp[0][j][k]);
        dp[1][j][max(k - 2, 0)] = add(dp[1][j][max(k - 2, 0)], dp[0][j][k]);
      }
    }
  }
}

main() {
  int p = 1;
  scanf("%d", &p);
  int test;
  scanf("%d", &test);
  if (p == 1) {
    while (test--) {
      string s;
      cin >> s;
      if (solve1(s) == 0) {
        puts("impossible");
      } else {
        for (int i = 0; i < sz(s); i++) {
          if (a[i] == 0) printf("R");
          else if (a[i] == 1) printf("G");
          else printf("B");
        }
        puts("");
      }
    }
  } else {
    solve2();
    while (test--) {
      int x;
      scanf("%d", &x);
      printf("%d\n", ans[x]);
    }
  }
}

Compilation message (stderr)

parentrises.cpp:123:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^
parentrises.cpp: In function 'int main()':
parentrises.cpp:125:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &p);
   ~~~~~^~~~~~~~~~
parentrises.cpp:127:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &test);
   ~~~~~^~~~~~~~~~~~~
parentrises.cpp:147:12: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
       scanf("%d", &x);
       ~~~~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 6 / 6
• Subtask 4: 28 / 28
• Subtask 5: 6 / 6
• Subtask 6: 16 / 16
• Subtask 7: 28 / 28