Submission #1248319

#	Time	Username	Problem	Language	Result	Execution time	Memory
1248319		Lithanium	Linear Garden (IOI08_linear_garden)	C++20	95 / 100	172 ms	74892 KiB

linear_garden

#include <bits/stdc++.h>
using namespace std;

bitset<1000005> num;
int dp01[1000005];
int dp10[1000005];
int dp11[1000005];
int N, M;

int read(int n, char L, char P) {
    if (L == 0 and P == 1) return dp01[n];
    if (L == 1 and P == 1) return dp11[n];
    if (L == 1 and P == 0) return dp10[n];
}

void write(int n, char L, char P, int x) {
    if (L == 0 and P == 1) dp01[n] = x;
    if (L == 1 and P == 1) dp11[n] = x;
    if (L == 1 and P == 0) dp10[n] = x;
}

int solve(int n, char L, char P, bool lim) {
    if (L > 2 or P > 2) return 0;
    if (n == N) return 1;
    if (!lim and max(L, P) == 1 and read(n, L, P) != -1) return read(n, L, P);
    int top = 1;
    if (lim and num[n+1] == 0) top = 0;
    int ans = 0;
    // put a 0
    if (L != 2) (ans += solve(n+1, L+1, max(0, P-1), lim and (top == 0))) %= M;
    // put a 1
    if (top and P != 2) (ans += solve(n+1, max(0, L-1), P+1, lim)) %= M;
    if (!lim and max(L, P) == 1) write(n, L, P, ans);
    return ans;
}

int main() {
    memset(dp01, -1, sizeof(dp01));
    memset(dp10, -1, sizeof(dp10));
    memset(dp11, -1, sizeof(dp11));
    cin >> N >> M;
    for (int i = 1; i <= N; i ++) {
        char c;
        cin >> c;
        if (c == 'P') num[i] = 1;
    }
    cout << solve(0, 0, 0, 1);
}

Compilation message (stderr)

linear_garden.cpp: In function 'int read(int, char, char)':
linear_garden.cpp:14:1: warning: control reaches end of non-void function [-Wreturn-type]
   14 | }
      | ^

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