Submission #1308069


Source Code Expand

import std.stdio, std.array, std.string, std.conv, std.algorithm;
import std.typecons, std.range, std.random, std.math, std.container;
import std.numeric, std.bigint, core.bitop;


immutable long MOD = 10^^9 + 7;

long powmod(long a, long x, long m) {
    long ret = 1;
    while (x) {
        if (x % 2) ret = ret * a % m;
        a = a * a % m;
        x /= 2;
    }
    return ret;
}

void main() {
    auto N = readln.chomp.to!int;
    auto S = readln.chomp;
    auto M = S.length.to!int;

    auto mem = new long[][](N + 1, N + 1);
    foreach (i; 0..N+1) fill(mem[i], -1);
   
    // dp(i, j) : i回キーを叩いてj文字入力されている場合の数
    long dp(int i, int j) {
        if (i == 0 && j == 0) return 1;
        if (i <= 0 || j < 0) return 0;
        if (j > i) return 0;
        if (mem[i][j] >= 0) return mem[i][j];

        long ret = 0;
        if (j == 0) {
            ret += dp(i - 1, j);
            ret %= MOD;
        }
        ret += dp(i - 1, j + 1); // Back Space
        ret %= MOD;
        ret += dp(i - 1, j - 1) * 2; // 0 or 1
        ret %= MOD;
        return mem[i][j] = ret;
    }


    auto ans = dp(N, M);
    ans = ans * powmod(powmod(2, MOD-2, MOD), M, MOD) % MOD;
    ans.writeln;
}

Submission Info

Submission Time
Task F - Unhappy Hacking
User nebukuro09
Language D (LDC 0.17.0)
Score 800
Code Size 1286 Byte
Status AC
Exec Time 315 ms
Memory 202876 KB

Judge Result

Set Name Sample Sub1 Sub2
Score / Max Score 0 / 0 400 / 400 400 / 400
Status
AC × 3
AC × 23
AC × 44
Set Name Test Cases
Sample 0_01, 0_02, 0_03
Sub1 0_01, 0_02, 1_04, 1_05, 1_06, 1_07, 1_08, 1_09, 1_10, 1_11, 1_12, 1_13, 1_14, 1_15, 1_16, 1_17, 1_18, 1_19, 1_20, 1_21, 1_22, 1_23, 1_24
Sub2 0_01, 0_02, 0_03, 1_04, 1_05, 1_06, 1_07, 1_08, 1_09, 1_10, 1_11, 1_12, 1_13, 1_14, 1_15, 1_16, 1_17, 1_18, 1_19, 1_20, 1_21, 1_22, 1_23, 1_24, 2_25, 2_26, 2_27, 2_28, 2_29, 2_30, 2_31, 2_32, 2_33, 2_34, 2_35, 2_36, 2_37, 2_38, 2_39, 2_40, 2_41, 2_42, 2_43, 2_44
Case Name Status Exec Time Memory
0_01 AC 1 ms 256 KB
0_02 AC 2 ms 2940 KB
0_03 AC 315 ms 201084 KB
1_04 AC 1 ms 256 KB
1_05 AC 2 ms 3068 KB
1_06 AC 2 ms 2940 KB
1_07 AC 2 ms 1532 KB
1_08 AC 2 ms 1532 KB
1_09 AC 2 ms 1532 KB
1_10 AC 2 ms 1532 KB
1_11 AC 2 ms 1532 KB
1_12 AC 2 ms 3452 KB
1_13 AC 2 ms 1532 KB
1_14 AC 2 ms 3452 KB
1_15 AC 2 ms 2428 KB
1_16 AC 2 ms 1532 KB
1_17 AC 2 ms 3452 KB
1_18 AC 2 ms 1532 KB
1_19 AC 2 ms 2684 KB
1_20 AC 1 ms 256 KB
1_21 AC 1 ms 636 KB
1_22 AC 1 ms 380 KB
1_23 AC 2 ms 2684 KB
1_24 AC 1 ms 764 KB
2_25 AC 266 ms 201596 KB
2_26 AC 261 ms 201084 KB
2_27 AC 217 ms 201980 KB
2_28 AC 80 ms 201980 KB
2_29 AC 79 ms 201084 KB
2_30 AC 247 ms 202876 KB
2_31 AC 210 ms 202876 KB
2_32 AC 244 ms 202108 KB
2_33 AC 98 ms 202108 KB
2_34 AC 202 ms 202748 KB
2_35 AC 208 ms 202236 KB
2_36 AC 94 ms 202108 KB
2_37 AC 163 ms 201852 KB
2_38 AC 197 ms 201596 KB
2_39 AC 147 ms 202236 KB
2_40 AC 104 ms 161148 KB
2_41 AC 97 ms 89852 KB
2_42 AC 216 ms 196732 KB
2_43 AC 133 ms 117500 KB
2_44 AC 3 ms 5372 KB