Add TypeScript examples for chapters 10 and 11 (#311)

Author: IgorJFS

10_greedy_algorithms/ts/01_set_covering.ts

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+// You pass an array in, and it gets converted to a set.
+let statesNeeded: Set<string> = new Set(["mt", "wa", "or", "id", "nv", "ut", "ca", "az"]);
+
+const stations: Record<string, Set<string>> = {};
+stations["kone"] = new Set(["id", "nv", "ut"]);
+stations["ktwo"] = new Set(["wa", "id", "mt"]);
+stations["kthree"] = new Set(["or", "nv", "ca"]);
+stations["kfour"] = new Set(["nv", "ut"]);
+stations["kfive"] = new Set(["ca", "az"]);
+
+const finalStations: Set<string> = new Set();
+
+while (statesNeeded.size) {
+  let bestStation: string | null = null;
+  let statesCovered: Set<string> = new Set();
+
+  for (let station in stations) {
+    const states = stations[station];
+    const covered = new Set([...statesNeeded].filter(x => states.has(x)));
+
+    if (covered.size > statesCovered.size) {
+      bestStation = station;
+      statesCovered = covered;
+    }
+  }
+
+  statesNeeded = new Set([...statesNeeded].filter(x => !statesCovered.has(x)));
+
+  if (bestStation !== null) {
+    finalStations.add(bestStation);
+  }
+}
+
+console.log(finalStations); // Set { 'kone', 'ktwo', 'kthree', 'kfive' }

10_greedy_algorithms/ts/tsconfig.json

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+{
+    "compilerOptions": {
+      "lib": [
+        "dom",
+        "es2015", 
+        "es2016",
+        "es2017"
+      ],
+      "target": "es2015" 
+    }
+  }
+  

11_dynamic_programming/ts/01_longest_common_subsequence.ts

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+/**
+ * Search for LCS
+ *
+ * @param {string} string1 first string
+ * @param {string} string2 second string
+ *
+ * @return {object} with keys: lcs, offset, sequence
+ */
+function lcs(string1: string, string2: string): { lcs: number; offset: number; sequence: string } {
+	if (typeof string1 !== "string" || typeof string2 !== "string" || !string1 || !string2) {
+		return {
+			lcs: 0,
+			offset: 0,
+			sequence: ""
+		};
+	}
+
+	let lcs = 0;
+	let lastSubIndex = 0;
+
+	const table: number[][] = [];
+	const len1 = string1.length;
+	const len2 = string2.length;
+
+	let row: number;
+	let col: number;
+
+	for (row = 0; row <= len1; row++) {
+		table[row] = [];
+		for (col = 0; col <= len2; col++) {
+			table[row][col] = 0;
+		}
+	}
+
+	let i: number;
+	let j: number;
+
+	for (i = 0; i < len1; i++) {
+		for (j = 0; j < len2; j++) {
+			if (string1[i] === string2[j]) {
+				if (table[i][j] === 0) {
+					table[i + 1][j + 1] = 1;
+				} else {
+					table[i + 1][j + 1] = table[i][j] + 1;
+				}
+
+				if (table[i + 1][j + 1] > lcs) {
+					lcs = table[i + 1][j + 1];
+					lastSubIndex = i;
+				}
+			} else {
+				table[i + 1][j + 1] = 0;
+			}
+		}
+	}
+
+	return {
+		lcs: lcs,
+		offset: lastSubIndex - lcs + 1,
+		sequence: string1.slice(lastSubIndex - lcs + 1, lastSubIndex + 1)
+	};
+}
+
+// Test cases
+console.log(lcs("hish", "fish")); // { lcs: 3, offset: 1, sequence: 'ish' }
+console.log(lcs("vista", "hish")); // { lcs: 2, offset: 1, sequence: 'is' }
+console.log(lcs("google", "abcdefgooglehijklm")); // { lcs: 6, offset: 0, sequence: 'google' }
+console.log(lcs("0", "0")); // { lcs: 1, offset: 0, sequence: '0' }
+console.log(lcs("0", 0 as any)); // { lcs: 0, offset: 0, sequence: '' }

11_dynamic_programming/ts/tsconfig.json

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+{
+    "compilerOptions": {
+      "lib": [
+        "dom",
+        "es2015", 
+        "es2016",
+        "es2017"
+      ],
+      "target": "es2015" 
+    }
+  }
+