<p>You are given two strings <code>current</code> and <code>correct</code> representing two <strong>24-hour times</strong>.</p>

<p>24-hour times are formatted as <code>&quot;HH:MM&quot;</code>, where <code>HH</code> is between <code>00</code> and <code>23</code>, and <code>MM</code> is between <code>00</code> and <code>59</code>. The earliest 24-hour time is <code>00:00</code>, and the latest is <code>23:59</code>.</p>

<p>In one operation you can increase the time <code>current</code> by <code>1</code>, <code>5</code>, <code>15</code>, or <code>60</code> minutes. You can perform this operation <strong>any</strong> number of times.</p>

<p>Return <em>the <strong>minimum number of operations</strong> needed to convert </em><code>current</code><em> to </em><code>correct</code>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> current = &quot;02:30&quot;, correct = &quot;04:35&quot;
<strong>Output:</strong> 3
<strong>Explanation:
</strong>We can convert current to correct in 3 operations as follows:
- Add 60 minutes to current. current becomes &quot;03:30&quot;.
- Add 60 minutes to current. current becomes &quot;04:30&quot;.
- Add 5 minutes to current. current becomes &quot;04:35&quot;.
It can be proven that it is not possible to convert current to correct in fewer than 3 operations.</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> current = &quot;11:00&quot;, correct = &quot;11:01&quot;
<strong>Output:</strong> 1
<strong>Explanation:</strong> We only have to add one minute to current, so the minimum number of operations needed is 1.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>current</code> and <code>correct</code> are in the format <code>&quot;HH:MM&quot;</code></li>
	<li><code>current &lt;= correct</code></li>
</ul>

class Solution {
public:
    int convertTime(string current, string correct) {
       int HH1=0,MM1=0;
       int HH2=0,MM2=0;

        for(int i=0;i<2;i++)
                HH1=HH1*10+(current[i]-'0');
        for(int i=3;i<5;i++) 
                MM1=MM1*10+(current[i]-'0');
        for(int i=0;i<2;i++)
                HH2=HH2*10+(correct[i]-'0');
        for(int i=3;i<5;i++) 
                MM2=MM2*10+(correct[i]-'0');
        int t1=HH1*60+MM1;
        int t2=HH2*60+MM2;
        int diff=abs(t2-t1);
        int count=0;
       while (diff > 0) {
            if (diff >= 60) {
                diff -= 60;
            } else if (diff >= 15) {
                diff -= 15;
            } else if (diff >= 5) {
                diff -= 5;
            } else {
                diff -= 1;
            }
            count++;
        }

        return count;
    }
};
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