提出 #631749

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ソースコード 拡げる

#include <bits/stdc++.h>
using namespace std;
const int MAXN = 1e9;
const int MAXP = 9;
typedef long long ll;
#define rep( i, a ) for(int i = 0; i < (a); ++i)

int n;
ll way[MAXP][MAXP][2];

int digit_count(int x){
    int res = 0;
    while( x > 0 ) x /= 10, ++res;
    return res;
}

int digit(int n, int m, int k){
    int g = m - k; // from the back
    rep( i, g ) n /= 10;
    return n % 10;
}

ll dp(int n, int m){
    memset( way, 0, sizeof(way) );
    way[0][0][0] = 1;
    rep( i, m ) rep( j, i + 1 ) rep( k, 2 ){
        int lim = k ? 9 : digit( n, m, i + 1 );
        rep( d, lim + 1 )
            way[i + 1][j + ( d == 1 )][k || d < lim] += way[i][j][k];
    }
    ll res = 0;
    rep( j, m + 1 ) rep( k, 2 )
        res += j * way[m][j][k];
    return res;
}

void solve(){
    int m = digit_count( n );
    printf("%lld\n", dp( n, m ));
}

int main(){
    scanf("%d", &n);
    solve();
    return 0;
}

提出情報

コンパイルエラー

./Main.cpp: In function ‘int main()’:
./Main.cpp:43:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &n);
                    ^

ジャッジ結果