Submission #37472

#	Time	Username	Problem	Language	Result	Execution time	Memory
37472		HardNut	Bootfall (IZhO17_bootfall)	C++14	65 / 100	1000 ms	3968 KiB

bootfall

#include<bits/stdc++.h>

using namespace std;

const int N = 250005;
const int mod = 1e9 + 7;

typedef long long ll;

int n, a[505], sum;
vector<int> vec;
int ans[N];
int dp[N];

void add(int v) {
    for (int i = sum; i >= 0; i--) {
        dp[i + v] += dp[i];
        if (dp[i + v] >= mod)
            dp[i + v] -= mod;
    }
    sum += v;
}

void del(int v) {
    sum -= v;
    for (int i = 0; i <= sum; i++) {
        dp[i + v] = (dp[i + v] - dp[i] + mod);
        if (dp[i + v] >= mod)
            dp[i + v] -= mod;
    }
}

int main() {
//    freopen("bootfall.in", "r", stdin);
//    freopen("bootfall.out", "w", stdout);
    scanf("%d", &n);
    dp[0] = 1;
    for (int i = 1; i <= n; i++) {
        scanf("%d", &a[i]);
        add(a[i]);
    }
    if (sum % 2 == 1) {
        cout << 0;
        return 0;
    }
    for (int i = 1; i <= sum; i++) {
        ans[i] = 1;
    }
    if (!dp[sum / 2]) {
        cout << 0;
        return 0;
    }
    for (int i = 1; i <= n; i++) {
        del(a[i]);
        for (int j = 1; j <= N; j++) {
            if ((sum + j) % 2) {
                ans[j] = 0;
                continue;
            }
            if (!dp[(sum + j) / 2]) {
                ans[j] = 0;
            }
        }
        add(a[i]);
    }
    int cnt = 0;
    for (int i = 1; i <= sum; i++) {
        cnt += ans[i];
    }
    printf("%d\n", cnt);
    for (int i = 1; i <= sum; i++)
        if (ans[i])
            printf("%d ", i);
}

Compilation message (stderr)

bootfall.cpp: In function 'int main()':
bootfall.cpp:36:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
                    ^
bootfall.cpp:39:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d", &a[i]);
                           ^

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 15 / 15
• Subtask 4: 16 / 16
• Subtask 5: 21 / 21
• Subtask 6: 0 / 35