From b1ea15d245220ffe9a86c6d6c1e1f1f409de30f6 Mon Sep 17 00:00:00 2001
From: Haidong Ji
Date: Tue, 25 Dec 2018 16:56:44 -0600
Subject: Woohoo, longest subsequence (3 seqs) done!

---
 PlaygroundCpp/Sources/Playground.cpp | 92 ++++++++++++++++++------------------
 1 file changed, 47 insertions(+), 45 deletions(-)

diff --git a/PlaygroundCpp/Sources/Playground.cpp b/PlaygroundCpp/Sources/Playground.cpp
index 8c8b854..e402792 100644
--- a/PlaygroundCpp/Sources/Playground.cpp
+++ b/PlaygroundCpp/Sources/Playground.cpp
@@ -5,61 +5,63 @@
 
 using std::vector;
 
-int lcs2(vector<int> &a, vector<int> &b) {
+int lcs3(vector<int> &a, vector<int> &b, vector<int> &c) {
+	int l = c.size();
 	int m = b.size();
 	int n = a.size();
-	int D[n + 1][m + 1];
-	for (int j = 0; j < m + 1; j++) {
-		for (int i = 0; i < n + 1; i++) {
-	// Initialize row/column 0 to 0 is necessary!
-			if (i == 0 || j == 0) {
-				D[i][j] = 0;
-				continue;
-			}
-			if (a.at(i - 1) == b.at(j - 1)) {
-				D[i][j] = D[i - 1][j - 1] + 1;
-			} else {
-				D[i][j] = std::max(D[i - 1][j], D[i][j - 1]);
+	int D[n + 1][m + 1][l + 1];
+	for (int k = 0; k < l + 1; k++) {
+		for (int j = 0; j < m + 1; j++) {
+			for (int i = 0; i < n + 1; i++) {
+				if (i == 0 || j == 0 || k == 0) {
+					D[i][j][k] = 0;
+					continue;
+				}
+				if (a[i - 1] == b[j - 1] && b[j - 1] == c[k - 1]) {
+					D[i][j][k] = D[i - 1][j - 1][k - 1] + 1;
+				} else {
+					D[i][j][k] = std::max(D[i - 1][j][k],
+							std::max(D[i][j - 1][k], D[i][j][k - 1]));
+				}
 			}
 		}
 	}
-	return D[n][m];
+	return D[n][m][l];
 }
 
-//TEST(LCS2, t1) {
-//	vector<int> a = { 2, 7, 5 };
-//	vector<int> b = { 2, 5 };
-//	ASSERT_EQ(2, lcs2(a, b));
-//}
-//
-//TEST(LCS2, t2) {
-//	vector<int> a = { 1, 9, 2, 5, 5, 5, 8, 3, 5, 11, 0, 2, 4, 1, 7, 4, 5, 9, 2,
-//			4, 0, 3, 1, 5, 8, 3, 5, 9, 7, 8, 4, 5, 6, 7 };
-//	vector<int> b = { 6, 3, 8, 3, 1, 8, 3, 5, 0, 9, 6, 8, 3, 5, 7, 9, 1, 4, 7,
-//			9, 3, 5, 9, 0, 1, 4, 2, 7, 5, 8, 9, 3, 5, 6, 1, 6, 3, 1, 6, 7, 3 };
-//	ASSERT_EQ(17, lcs2(a, b));
+//TEST(LCS3, t1) {
+//	vector<int> a = { 1, 2, 3 };
+//	vector<int> b = { 2, 1, 3 };
+//	vector<int> c = { 1, 3, 5 };
+//	ASSERT_EQ(2, lcs3(a, b, c));
 //}
 //
-//TEST(LCS2, t3) {
-//	vector<int> a = { 1, 2, 3 };
-//	vector<int> b = { 3, 2, 1 };
-//	ASSERT_EQ(1, lcs2(a, b));
+//TEST(LCS3, t2) {
+//	vector<int> a = { 8, 3, 2, 1, 7 };
+//	vector<int> b = { 8, 2, 1, 3, 8, 10, 7 };
+//	vector<int> c = { 6, 8, 3, 1, 4, 7 };
+//	ASSERT_EQ(3, lcs3(a, b, c));
 //}
 
 int main() {
-  size_t n;
-  std::cin >> n;
-  vector<int> a(n);
-  for (size_t i = 0; i < n; i++) {
-    std::cin >> a[i];
-  }
-
-  size_t m;
-  std::cin >> m;
-  vector<int> b(m);
-  for (size_t i = 0; i < m; i++) {
-    std::cin >> b[i];
-  }
-
-  std::cout << lcs2(a, b) << std::endl;
+	size_t an;
+	std::cin >> an;
+	vector<int> a(an);
+	for (size_t i = 0; i < an; i++) {
+		std::cin >> a[i];
+	}
+	size_t bn;
+	std::cin >> bn;
+	vector<int> b(bn);
+	for (size_t i = 0; i < bn; i++) {
+		std::cin >> b[i];
+	}
+	size_t cn;
+	std::cin >> cn;
+	vector<int> c(cn);
+	for (size_t i = 0; i < cn; i++) {
+		std::cin >> c[i];
+	}
+	std::cout << lcs3(a, b, c) << std::endl;
 }
+
-- 
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