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pls give potimize and correct small code in c++.

생성일: 2026년 5월 16일

답변에 사용된 모델 GPT-5.5 Thinking by Chat01

질문

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pls give potimize and correct small code in c++.

사고

Analyzing optimization problem and restating calculated formula

The user is asking for coding optimization, specifically in C++. The string has a length of 2500, and I need to process pairs of characters. If they match, there's a cost. I think the formula becomes: extra time = sameTime * number of matching pairs + partitionTime * (number of partitions - 1). Let me break it down and compute it using these variables.

Optimizing string partition with dynamic programming

I can split the string into substrings, where each partition adds time but matches increase costs. For example, for "abccabcc," pairing characters like "cc" increase costs. The formula involves counting character pairs and minimizing total time. Since the length is 2500, I need to use dynamic programming to handle this efficiently and avoid overflow. I'll precompute pair counts and calculate the minimal cost for each substring partition dynamically, ensuring the solution properly handles integer overflow.

Thought for 1m 19s

답변

Use this optimized DP code inside the given function:

cpp
int getMinimumTime(int sameTime, int partitionTime, string s) {
    int n = s.size();
    const long long INF = 4e18;

    vector<long long> dp(n + 1, INF);
    dp[0] = 0;

    for (int i = 1; i <= n; i++) {
        vector<long long> freq(256, 0);
        long long extraCost = 0;

        // Try every possible last partition: s[j ... i-1]
        for (int j = i - 1; j >= 0; j--) {
            unsigned char ch = s[j];

            // Adding s[j] creates freq[ch] new matching pairs
            extraCost += freq[ch] * 1LL * sameTime;
            freq[ch]++;

            long long cutCost = (j == 0 ? 0 : partitionTime);
            dp[i] = min(dp[i], dp[j] + cutCost + extraCost);
        }
    }

    return (int)dp[n];
}

Logic: dp[i] = minimum extra time for prefix s[0...i-1].

For every ending position i, we move j backward and compute the matching-pair cost of substring s[j...i-1] on the fly.
Time complexity is O(n^2), which is fine for n <= 2500.

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