Submission #1209490

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(int i=a;i<b;i++)



int mod = 1000000007;
int add(int x, int y) { return (x += y) >= mod ? x - mod : x; }
template<class... T> int add(int x, T... y) { return add(x, add(y...)); }
int mul(int x, int y) { return 1LL * x * y % mod; }
template<class... T> int mul(int x, T... y) { return mul(x, mul(y...)); }
int sub(int x, int y) { return add(x, mod - y); }
int modpow(int a, long long b) {
    int ret = 1;
    while (b > 0) {
        if (b & 1) ret = 1LL * ret * a % mod;
        a = 1LL * a * a % mod; b >>= 1;
    }
    return ret;
}
int modinv(int a) { return modpow(a, mod - 2); }

int fac[201010], ifac[201010];
void initfac() {
    fac[0] = ifac[0] = 1;
    rep(i, 1, 201010) fac[i] = 1LL * i * fac[i - 1] % mod;
    rep(i, 1, 201010) ifac[i] = modinv(fac[i]);
}
int aCb(int a, int b) {
    if (b < 0 || a < b) return 0;
    return (1LL * fac[a] * ifac[a - b] % mod) * ifac[b] % mod;
}
int N, M, X[101010], Y[101010];
//-----------------------------------------------------------------------------------
int smx, smy;
int x[101010], y[101010];
int dpx[101010], dpy[101010];
void calc_sm() {
    rep(i, 0, N - 1) x[i] = (X[i + 1] - X[i]) % mod;
    rep(i, 0, M - 1) y[i] = (Y[i + 1] - Y[i]) % mod;

    dpx[0] = x[0];
    rep(i, 1, N - 1) dpx[i] = add(dpx[i - 1], mul(i + 1, x[i]));
    rep(i, 0, N - 1) smx = add(smx, dpx[i]);

    dpy[0] = y[0];
    rep(i, 1, M - 1) dpy[i] = add(dpy[i - 1], mul(i + 1, y[i]));
    rep(i, 0, M - 1) smy = add(smy, dpy[i]);
}
//-----------------------------------------------------------------------------------
int main() {
    initfac();

    cin >> N >> M;
    rep(i, 0, N) scanf("%d", &X[i]);
    rep(i, 0, M) scanf("%d", &Y[i]);

    calc_sm();

    cout << mul(smx, smy) << endl;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:55:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     rep(i, 0, N) scanf("%d", &X[i]);
                                    ^
./Main.cpp:56:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     rep(i, 0, M) scanf("%d", &Y[i]);
                                    ^

Judge Result