[Create] BOJ_1149 RGB거리

RGBTown.java

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+// 백준_1149
+// 2021.04.07
+// Dynamic Programming
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.StringTokenizer;
+
+class RGBTown {
+    public static void main(String[] args) throws IOException {
+        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+        StringTokenizer st = new StringTokenizer(br.readLine());
+        int N = Integer.valueOf(st.nextToken());
+
+        int[][] cost = new int[N][3];
+        int[][] memory = new int[N][3];
+
+
+        for (int i = 0; i < N; i++) {
+            st = new StringTokenizer(br.readLine());
+            cost[i][0] = Integer.valueOf(st.nextToken());
+            cost[i][1] = Integer.valueOf(st.nextToken());
+            cost[i][2] = Integer.valueOf(st.nextToken());
+        }
+
+        memory[0][0] = cost[0][0];
+        memory[0][1] = cost[0][1];
+        memory[0][2] = cost[0][2];
+
+        for (int i = 1; i < N; i++) {
+            memory[i][0] = Math.min(memory[i - 1][1], memory[i - 1][2]) + cost[i][0];
+            memory[i][1] = Math.min(memory[i - 1][0], memory[i - 1][2]) + cost[i][1];
+            memory[i][2] = Math.min(memory[i - 1][1], memory[i - 1][0]) + cost[i][2];
+        }
+
+        System.out.println(Math.min(Math.min(memory[N - 1][0], memory[N - 1][1]), memory[N - 1][2]));
+    }
+}
+
+
+/*
+// USE Recursive
+// 출처_https://st-lab.tistory.com/
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+import java.io.IOException;
+import java.util.StringTokenizer;
+
+public class Main {
+
+	final static int Red = 0;
+	final static int Green = 1;
+	final static int Blue = 2;
+
+	static int[][] Cost;
+	static int[][] DP;
+
+	public static void main(String[] args) throws IOException {
+
+		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
+
+		int N = Integer.parseInt(br.readLine());
+		Cost = new int[N][3];
+		DP = new int[N][3];
+
+		StringTokenizer st;
+		for(int i = 0; i < N; i++) {
+
+			st = new StringTokenizer(br.readLine(), " ");
+
+			Cost[i][Red] = Integer.parseInt(st.nextToken());
+			Cost[i][Green] = Integer.parseInt(st.nextToken());
+			Cost[i][Blue] = Integer.parseInt(st.nextToken());
+		}
+
+		// DP의 첫번째 값(집)은 각 색상비용의 첫번째 값으로 초기화
+		DP[0][Red] = Cost[0][Red];
+		DP[0][Green] = Cost[0][Green];
+		DP[0][Blue] = Cost[0][Blue];
+
+
+		System.out.println(Math.min(Paint_cost(N- 1, Red), Math.min(Paint_cost(N - 1, Green), Paint_cost(N - 1, Blue))));
+	}
+
+	static int Paint_cost(int N, int color) {
+
+		// 만약 탐색하지 않은 배열이라면
+		if(DP[N][color] == 0) {
+
+			// color의 색에 따라 이전 집의 서로 다른 색을 재귀호출하여 최솟값과 현재 집의 비용을 더해서 DP에 저장한다
+			if(color == Red) {
+				DP[N][Red] = Math.min(Paint_cost(N - 1, Green), Paint_cost(N - 1, Blue)) + Cost[N][Red];
+			}
+			else if(color == Green) {
+				DP[N][Green] = Math.min(Paint_cost(N - 1, Red), Paint_cost(N - 1, Blue)) + Cost[N][Green];
+			}
+			else {
+				DP[N][Blue] = Math.min(Paint_cost(N - 1, Red), Paint_cost(N - 1, Green)) + Cost[N][Blue];
+			}
+
+		}
+
+		return DP[N][color];
+	}
+}
+ */