import(solutions): Add problem 746 .

1 files changed, 35 insertions, 0 deletions

diff --git a/works/solutions/cpp/746.cpp b/works/solutions/cpp/746.cpp
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+++ b/works/solutions/cpp/746.cpp
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+#include <vector>
+
+using std::vector;
+
+#include <algorithm>
+
+class Solution
+{
+public:
+    int minCostClimbingStairs(vector<int> &cost)
+    {
+        int count = cost.size();
+
+        // Total cost for index i means min cost of stepping through the number i stair,
+        // after which you are free to jump two or one stair.
+        // total_costs[i] is based on total_costs[i - 2] and total_costs[i - 1].
+        // Note:
+        // This is not min cost to step above the number i stair, which has no simple dependency
+        // relationship because based on whether it steps through the last step there are two situation.
+        // However with the restriction of stepping through that last stair, there is a
+        // dependency relationship. And we can easily get the final result by comparing total_costs[count - 2]
+        // and total_costs[count - 1]. But not just use total_costs[count - 1].
+        vector<int> total_costs(count);
+
+        total_costs[0] = cost[0];
+        total_costs[1] = cost[1];
+
+        for (int i = 2; i < count; i++)
+        {
+            total_costs[i] = std::min(total_costs[i - 2], total_costs[i - 1]) + cost[i];
+        }
+
+        return std::min(total_costs[count - 2], total_costs[count - 1]);
+    }
+};