five functions in C that could be faster

optimize.c

#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>


int count(uint64_t x) {
    int count = 0;
    for(int k = 0; k < 64; k++) {
        count += (x&1);
        x >>= 1;
    }
    return count;
}

uint64_t prefix(uint64_t * x, int length) {
    if(length == 0) { return 0; }
    uint64_t * array = ( uint64_t *)malloc(length * sizeof(uint64_t));
    array[0] = x[0];
    for(int k = 1; k < length; k++) {
        array[k] = x[k] + array[k-1];
    }
    uint64_t answer = array[length-1];
    free(array);
    return answer;
}



bool match(const char * x) {
    bool answer = false;
    for(int k = 0; k < 1000; k++) {
        if(x[k] == 'c' || x[k] == 'z' || x[k] == '"' || x[k] == '*' || x[k] == '&') {
            answer = true;
        }
    }
    return answer;
}


bool digit(const char * x) {
    bool answer = true;
    for(int k = 0; k < 8; k++) {
        answer &= (x[k] >= '0' && x[k] <= '9');
    }
    return answer;
}

uint64_t unique(uint64_t * x, int length) {
    bool uni = true;
    for(int k = 0; k < length; k++) {
        uint64_t current = x[k];
        int count = 0;
        for(int l = 0; l < length; l++) {
            if(x[l] == current) { count ++;}
        }
        if(count != 1) { uni = false; }
    }
    return uni;
}