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Submission #171635

# Submission time Handle Problem Language Result Execution time Memory
171635 2019-12-29T12:41:45 Z Milki Ljetopica (COI19_ljetopica) C++14
100 / 100
 156 ms 32248 KB 
#include<bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = a; i < b; ++i)
#define REP(i, n) FOR(i, 0, n)
#define _ << " " <<
#define sz(x) ((int) x.size())
#define pb(x) push_back(x)
#define TRACE(x) cerr << #x << " = " << x << endl

typedef long long ll;
typedef pair<int, int> point;

const int mod = 1e9 + 7;

int add(int x, int y) {x += y; if(x >= mod) return x - mod; return x;}
int sub(int x, int y) {x -= y; if(x < 0) return x + mod; return x;}
int mul(int x, int y) {return (ll) x * y % mod;}

const int MAXN = 1e3 + 5;

int n, k, pot[MAXN];
string s, A, B;
point dp[MAXN][MAXN][2][2];

bool reduce(string &border){
  bool ret = false;
  REP(i, sz(border))
    if(border[i] == '1')
      ret = true;

  for(int i = sz(border) - 1; i >= 0; --i)
    if(border[i] == '1'){
      border[i] = '0';
      FOR(j, i + 1, sz(border))
        border[j] = '1';
      break;
    }
  return ret;
}

point rek(int depth, int changes, bool flipped, bool take_all, string &border){
  point &ret = dp[depth][changes][flipped][take_all];
  if(ret != point(-1, -1)) return ret;
  if(changes > k) return ret = {0, 0};
  if(depth == n - 1){
    if(changes == k) { return ret = {1, 0}; }
    else return ret = {0, 0};
  }

  int border_value = (border[depth + 1] == '1');
  int curr_value = (s[depth] == 'R');
  if(flipped) curr_value = !curr_value;

  if(!take_all && curr_value < border_value)
    take_all = true;
  if(!take_all && curr_value > border_value)
    return ret = {0, 0};

  int ways = 0, sum = 0;

  REP(flip, 2){
    if(depth == n - 2 && flip == 1) continue;

    int new_flip = flipped ^ flip;
    point tmp = rek(depth + 1, changes + flip, new_flip, take_all, border);
    ways = add(ways, tmp.first);
    sum = add(sum, tmp.second);
  }
  if(curr_value)
    sum = add(sum, mul(ways, pot[n - depth - 2]));

  return ret = {ways, sum};
}

void merge(point &A, point &B){
  A.first = add(A.first, B.first);
  A.second = add(A.second, B.second);
}

int solve(string &border){
  if(border[0] == '0') return 0;

  REP(i, MAXN) REP(j, MAXN) REP(it1, 2) REP(it2, 2)
    dp[i][j][it1][it2] = {-1, -1};

  point ret1 = rek(0, 0, false, false, border);
  point ret2 = rek(0, 1, true, false, border);
  point ret3 = rek(0, 0, true, false, border);
  point ret4 = rek(0, 1, false, false, border);

  merge(ret1, ret2);
  merge(ret1, ret3);
  merge(ret1, ret4);

  return add(ret1.second, mul(ret1.first, pot[n - 1]));
}

int main(){
  ios_base::sync_with_stdio(false); cin.tie(0);

  pot[0] = 1;
  FOR(i, 1, MAXN)
    pot[i] = mul(pot[i - 1], 2);

  cin >> n >> k;
  cin >> s >> A >> B;

  if(!reduce(A))
    cout << solve(B);
  else
    cout << sub( solve(B), solve(A) );
  //reduce(A); cout << solve(A);
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 36 ms 32120 KB Output is correct
2 Correct 36 ms 32120 KB Output is correct
3 Correct 36 ms 32120 KB Output is correct
4 Correct 35 ms 32120 KB Output is correct
5 Correct 36 ms 31992 KB Output is correct
6 Correct 36 ms 32120 KB Output is correct
7 Correct 43 ms 32120 KB Output is correct
8 Correct 35 ms 31992 KB Output is correct

Subtask #2
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 41 ms 31992 KB Output is correct
2 Correct 40 ms 31992 KB Output is correct
3 Correct 43 ms 31964 KB Output is correct
4 Correct 35 ms 31992 KB Output is correct
5 Correct 36 ms 31992 KB Output is correct
6 Correct 35 ms 31992 KB Output is correct
7 Correct 37 ms 31992 KB Output is correct
8 Correct 36 ms 32120 KB Output is correct
9 Correct 41 ms 31992 KB Output is correct
10 Correct 41 ms 31992 KB Output is correct
11 Correct 36 ms 31992 KB Output is correct
12 Correct 36 ms 32008 KB Output is correct
13 Correct 40 ms 31964 KB Output is correct
14 Correct 41 ms 31992 KB Output is correct
15 Correct 37 ms 31992 KB Output is correct

Subtask #3
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 73 ms 32124 KB Output is correct
2 Correct 64 ms 32120 KB Output is correct
3 Correct 67 ms 32120 KB Output is correct
4 Correct 118 ms 31996 KB Output is correct
5 Correct 64 ms 32120 KB Output is correct
6 Correct 125 ms 32120 KB Output is correct
7 Correct 56 ms 32120 KB Output is correct
8 Correct 83 ms 32092 KB Output is correct
9 Correct 44 ms 32120 KB Output is correct
10 Correct 65 ms 32120 KB Output is correct

Subtask #4
61.0 / 61.0

# Verdict Execution time Memory Grader output
1 Correct 36 ms 32120 KB Output is correct
2 Correct 36 ms 32120 KB Output is correct
3 Correct 36 ms 32120 KB Output is correct
4 Correct 35 ms 32120 KB Output is correct
5 Correct 36 ms 31992 KB Output is correct
6 Correct 36 ms 32120 KB Output is correct
7 Correct 43 ms 32120 KB Output is correct
8 Correct 35 ms 31992 KB Output is correct
9 Correct 41 ms 31992 KB Output is correct
10 Correct 40 ms 31992 KB Output is correct
11 Correct 43 ms 31964 KB Output is correct
12 Correct 35 ms 31992 KB Output is correct
13 Correct 36 ms 31992 KB Output is correct
14 Correct 35 ms 31992 KB Output is correct
15 Correct 37 ms 31992 KB Output is correct
16 Correct 36 ms 32120 KB Output is correct
17 Correct 41 ms 31992 KB Output is correct
18 Correct 41 ms 31992 KB Output is correct
19 Correct 36 ms 31992 KB Output is correct
20 Correct 36 ms 32008 KB Output is correct
21 Correct 40 ms 31964 KB Output is correct
22 Correct 41 ms 31992 KB Output is correct
23 Correct 37 ms 31992 KB Output is correct
24 Correct 73 ms 32124 KB Output is correct
25 Correct 64 ms 32120 KB Output is correct
26 Correct 67 ms 32120 KB Output is correct
27 Correct 118 ms 31996 KB Output is correct
28 Correct 64 ms 32120 KB Output is correct
29 Correct 125 ms 32120 KB Output is correct
30 Correct 56 ms 32120 KB Output is correct
31 Correct 83 ms 32092 KB Output is correct
32 Correct 44 ms 32120 KB Output is correct
33 Correct 65 ms 32120 KB Output is correct
34 Correct 139 ms 32120 KB Output is correct
35 Correct 74 ms 32116 KB Output is correct
36 Correct 92 ms 31992 KB Output is correct
37 Correct 118 ms 32120 KB Output is correct
38 Correct 56 ms 32120 KB Output is correct
39 Correct 111 ms 32120 KB Output is correct
40 Correct 52 ms 32120 KB Output is correct
41 Correct 106 ms 32120 KB Output is correct
42 Correct 115 ms 32120 KB Output is correct
43 Correct 113 ms 31992 KB Output is correct
44 Correct 111 ms 32120 KB Output is correct
45 Correct 75 ms 32120 KB Output is correct
46 Correct 107 ms 32112 KB Output is correct
47 Correct 111 ms 32140 KB Output is correct
48 Correct 104 ms 32120 KB Output is correct
49 Correct 46 ms 32048 KB Output is correct
50 Correct 138 ms 32152 KB Output is correct
51 Correct 105 ms 32128 KB Output is correct
52 Correct 97 ms 32152 KB Output is correct
53 Correct 156 ms 32224 KB Output is correct
54 Correct 78 ms 32156 KB Output is correct
55 Correct 120 ms 32128 KB Output is correct
56 Correct 130 ms 32120 KB Output is correct
57 Correct 50 ms 32248 KB Output is correct
58 Correct 115 ms 32120 KB Output is correct