256.cpp

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class Solution {
public:
    int minCost(vector<vector<int>>& costs) {
        if (costs.empty() || costs[0].empty()) return 0;
        vector<vector<int>> dp = costs;
        for (int i = 1; i < dp.size(); ++i) {
            for (int j = 0; j < 3; ++j) {
                dp[i][j] += min(dp[i - 1][(j + 1) % 3], dp[i - 1][(j + 2) % 3]);
            }
        }
        return min(min(dp.back()[0], dp.back()[1]), dp.back()[2]);
    }
};
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class Solution {
public:
    int minCost(vector<vector<int>>& costs) {
        if (costs.empty() || costs[0].empty()) return 0;
        vector<vector<int>> dp = costs;
        for (int i = 1; i < dp.size(); ++i) {
            dp[i][0] += min(dp[i - 1][1], dp[i - 1][2]);
            dp[i][1] += min(dp[i - 1][0], dp[i - 1][2]);
            dp[i][2] += min(dp[i - 1][0], dp[i - 1][1]);
        }
        return min(min(dp.back()[0], dp.back()[1]), dp.back()[2]);
    }
};
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