Submission #1070836

#	Time	Username	Problem	Language	Result	Execution time	Memory
1070836		matthew	XORanges (eJOI19_xoranges)	C++17	100 / 100	76 ms	8436 KiB

xoranges

#include <stdio.h>
#include <assert.h>

const int MAXN = 200'000;

int v[MAXN + 1];

// poate fi optimizat la un singur N de memorie
int aib_par[MAXN + 1];
int aib_impar[MAXN + 1];

void pointUpdate(int *aib, int pos, int delta, int n) {
  while(pos <= n) {
    aib[pos] ^= delta;
    pos += pos & -pos;
  }
}

int prefixQuery(int *aib, int pos) {
  int res = 0;
  while(pos > 0) {
    res ^= aib[pos];
    pos &= pos - 1;
  }
  return res;
}

static inline int rangeQuery(int *aib, int l, int r) {
  return prefixQuery(aib, r) ^ prefixQuery(aib, l - 1);
}

int main() {
  #ifdef LOCAL
freopen("input.txt", "r", stdin);
  #endif

  int n, q, i, l, r, type, pos, val;

  scanf("%d%d", &n, &q);
  for(i = 1; i <= n; i++) {
    scanf("%d", &v[i]);
    pointUpdate((i & 1) ? aib_impar : aib_par, i, v[i], n);
  }

  for(i = 0; i < q; i++) {
    scanf("%d", &type);

    if(type == 2) {
      scanf("%d%d", &l, &r);

      if((r - l) & 1) {
        printf("0\n");
      } else {
        printf("%d\n", rangeQuery((l & 1) ? aib_impar : aib_par, l, r));
      }
    } else {
      scanf("%d%d", &pos, &val);
      pointUpdate((pos & 1) ? aib_impar : aib_par, pos, v[pos] ^ val, n);
      v[pos] = val;
    }
  }

  return 0;
}

Compilation message (stderr)

xoranges.cpp: In function 'int main()':
xoranges.cpp:39:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |   scanf("%d%d", &n, &q);
      |   ~~~~~^~~~~~~~~~~~~~~~
xoranges.cpp:41:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |     scanf("%d", &v[i]);
      |     ~~~~~^~~~~~~~~~~~~
xoranges.cpp:46:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   46 |     scanf("%d", &type);
      |     ~~~~~^~~~~~~~~~~~~
xoranges.cpp:49:12: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   49 |       scanf("%d%d", &l, &r);
      |       ~~~~~^~~~~~~~~~~~~~~~
xoranges.cpp:57:12: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   57 |       scanf("%d%d", &pos, &val);
      |       ~~~~~^~~~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 18 / 18
• Subtask 3: 25 / 25
• Subtask 4: 20 / 20
• Subtask 5: 25 / 25