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PermCheck.c
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PermCheck.c
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// PermCheck
#include <string.h>
void clear_bit(unsigned int * A, int idx) {
int dword_idx = idx / 32;
int internal_idx = idx % 32;
// printf("shutdown bit %d, dword_idx %d, internal idx %d, A[dword_idx] %08X \n", idx, dword_idx, internal_idx, A[dword_idx]);
A[dword_idx] &= ~(1U << internal_idx);
// printf("shotdownbit bit A[dword_idx] %08X\n", A[dword_idx]);
}
int is_clean_bit(unsigned int * A, int idx) {
int dword_idx = idx / 32;
int internal_idx = idx % 32;
if (A[dword_idx] & (1U << internal_idx)) {
return 0;
} else {
return 1;
}
}
int solution(int A[], int N) {
// write your code in C99 (gcc 6.2.0)
int min_value = 1;
int max_value = N;
int dword_l = N/32;
if (N%32 > 0) {
dword_l++;
}
unsigned int * bits = (unsigned int *)malloc(dword_l*4);
memset(bits, 0xFFU, dword_l*4);
int i;
for (i=N+1; i<=dword_l*32; i++) {
clear_bit(bits, i-min_value);
}
for (i=0; i<N; i++) {
if (0 >= A[i] || A[i] > max_value) {
return 0;
}
if (is_clean_bit(bits, A[i]-min_value)) {
return 0;
}
clear_bit(bits, A[i]-min_value);
}
for(i=0; i<dword_l; i++) {
if (bits[i] > 0) {
return 0;
}
}
return 1;
}