Submission #1007112

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Source Code Expand

#include <algorithm>
#include <cassert>
#include <cstring>
#include <iostream>

using namespace std;

#define FOR(i, a, b) for (int i = (a); i < (b); ++i)
#define REP(i, n) FOR(i, 0, n)
#define TRACE(x) cout << #x << " = " << x << endl
#define _ << " _ " <<

typedef long long llint;

const int MAX = 303;
const int mod = 1e9 + 7;

inline int add(int a, int b) {
  return a+b >= mod ? a+b-mod : a+b;
}

inline int sub(int a, int b) {
  return a >= b ? a-b : a-b+mod;
}

inline int mul(int a, int b) {
  return llint(a)*b % mod;
}

int c[MAX][MAX];
int f[MAX][MAX][MAX];
int pw[MAX*MAX];

int main(void) {
  int N;
  scanf("%d", &N);
  REP(i, N) REP(j, N) scanf("%d", &c[i][j]);


  int r = 0;
  REP(i, N) {
    int k = -1;
    FOR(j, r, N)
      if (c[j][i]) { k = j; break; }
    if (k == -1) continue;
      
    REP(j, N) swap(c[r][j], c[k][j]);
    REP(j, N)
      if (j != r && c[j][i])
        REP(k, N) c[j][k] ^= c[r][k];
    r++;
  }

  pw[0] = 1;
  FOR(i, 1, MAX*MAX) pw[i] = mul(pw[i-1], 2);
  
  f[0][0][0] = 1;
  REP(i, N) REP(rc, min(i+1, r+1)) REP(rn, min(i+1-rc, N-r+1)) {
    f[i+1][rc][rn] = add(f[i+1][rc][rn], mul(pw[rc+rn], f[i][rc][rn]));
    if (rc < r) {
      f[i+1][rc+1][rn] = add(f[i+1][rc+1][rn], mul(sub(pw[r+rn], pw[rc+rn]), f[i][rc][rn]));
    }
    if (rn < N-r) {
      f[i+1][rc][rn+1] = add(f[i+1][rc][rn+1], mul(sub(pw[N], pw[r+rn]), f[i][rc][rn]));
    }
  }

  int ans = 0;
  REP(rn, N-r+1) ans = add(ans, mul(pw[N*(N-rn-r)], f[N][r][rn]));
  printf("%d\n", ans);
  return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:36:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &N);
                  ^
./Main.cpp:37:44: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   REP(i, N) REP(j, N) scanf("%d", &c[i][j]);
                                            ^

Judge Result