C 解法, 执行用时: 2ms, 内存消耗: 336KB, 提交时间: 2020-09-08

/**
 * 
 * @param index int整型 
 * @return int整型
 */
int GetUglyNumber_Solution(int index ) {
    // write code here
    int ugly_count = 0;    // recording how many Ugly Number has found
    int ugly_buf[index];
    int index2, index3, index5;
    int last2, last3, last5, minium;
    
    if (index < 1)
    { return 0; }
    
    ugly_buf[0] = 1;
    index2 = 0;
    index3 = 0;
    index5 = 0;
    for (ugly_count = 1; ugly_count < index; ugly_count++)
    {
        last2 = ugly_buf[index2] * 2;
        last3 = ugly_buf[index3] * 3;
        last5 = ugly_buf[index5] * 5;
        if (last2 <= last3)    // find the minium value of last2.3.5
        {
            if (last2 <= last5)
            { minium = last2; }
            else
            { minium = last5; }
        }
        else
        {
            if (last3 <= last5)
            { minium = last3; }
            else
            { minium = last5; }
        }
        
        if (last2 == minium)
        { index2++; }
        if (last3 == minium)
        { index3++; }
        if (last5 == minium)
        { index5++; }
        
        ugly_buf[ugly_count] = minium;
    }
    return ugly_buf[index - 1];
}

C 解法, 执行用时: 2ms, 内存消耗: 348KB, 提交时间: 2021-02-18

/**
 * 
 * @param index int整型 
 * @return int整型
 */
int GetUglyNumber_Solution(int index ) {
    // write code here
    int array[index];
    array[0] = 1;
    if(index<=0) return 0;
    int p2 =0,p3=0,p5=0,temp,temp2,temp3,temp5;
    for(int i = 1;i<index;i++){
        //arr[i] = (((arr[p2]*2 < arr[p3]*3)?arr[p2]*2:arr[p3]*3)<arr[p5]*5)?((arr[p2]*2 < arr[p3]*3)?arr[p2]*2:arr[p3]*3):arr[p5]*5;
        temp2 = 2 * array[p2];
        temp3 = 3 * array[p3];
        temp5 = 5 * array[p5];
        temp = (temp2 < temp3) ? temp2 : temp3;
        temp = (temp < temp5) ? temp : temp5;
        array[i] = temp;
        if(temp == temp2) p2++;
        if(temp == temp3) p3++;
        if(temp == temp5) p5++;
    }
    return array[index-1];
}

C 解法, 执行用时: 2ms, 内存消耗: 348KB, 提交时间: 2021-02-10

/**
 *
 * @param index int整型
 * @return int整型
 */
int min(int a, int b, int c)
{
    if(a <= b && a <= c)
    {
        return a;
    }
    else if(b <= a && b <= c)
    {
        return b;
    }
    else if(c <= a && c <= b)
    {
        return c;
    }
    else
        return 0;
}
 
int GetUglyNumber_Solution(int index ) {
    if(index <= 0)
        return 0;
    int a[100000000];
    a[0] = 1;
    int p2 = 0, p3 = 0, p5 = 0, i;
    int j = 0;
    //a[1] = min(p2*2, p3*3, p5*5);
    for(i = 1; i <= index; i++)
    {
        a[i] = min(a[p2]*2, a[p3]*3, a[p5]*5);
        if(a[i]%2 == 0) p2++;
        if(a[i]%3 == 0) p3++;
        if(a[i]%5 == 0) p5++;
    }
    return a[index-1];
}

C 解法, 执行用时: 2ms, 内存消耗: 348KB, 提交时间: 2020-12-17

/**
 * 
 * @param index int整型 
 * @return int整型
 */
int GetUglyNumber_Solution(int index ) {
    // write code here
    int arr[index];
    int i2 = 1, i3 = 1, i5 =1;
    
    arr[0] = 0;
    arr[1] = 1;
    
    int tmp, tmp2, tmp3, tmp5;
    for(int i=1; i<index; i++)
    {
        tmp2 = 2*arr[i2];
        tmp3 = 3*arr[i3];
        tmp5 = 5*arr[i5];
        tmp = (tmp2<tmp3)?tmp2:tmp3;
        tmp = (tmp<tmp5)?tmp:tmp5;
        arr[i+1] = tmp;
        if(tmp == tmp2)
            i2++;
        if(tmp == tmp3)
            i3++;
        if(tmp == tmp5)
            i5++;
    }
    return arr[index];
}

C 解法, 执行用时: 2ms, 内存消耗: 352KB, 提交时间: 2021-03-14

/**
 * 
 * @param index int整型 
 * @return int整型
 */
#define min(a,b,c) a>b? b>c ? c:b :a>c? c:a
int GetUglyNumber_Solution(int index ) {
    // write code here
    if(index < 7) return index;
    int ret[index];
    ret[0] = 1;
    int po2=0,po3=0,po5=0;
    for(int i=1;i<index;++i){
        ret[i] = min(ret[po2]*2,ret[po3]*3,ret[po5]*5);
        if(ret[i] == ret[po2]*2) po2++;
        if(ret[i] == ret[po3]*3) po3++;
        if(ret[i] == ret[po5]*5) po5++;
    }
    return ret[index-1];
}