Data update

Task/State-name-puzzle/JavaScript/state-name-puzzle.js

@@ -0,0 +1,76 @@
+const states = ["Alabama", "Alaska", "Arizona", "Arkansas",
+    "California", "Colorado", "Connecticut",
+    "Delaware",
+    "Florida", "Georgia", "Hawaii",
+    "Idaho", "Illinois", "Indiana", "Iowa",
+    "Kansas", "Kentucky", "Louisiana",
+    "Maine", "Maryland", "Massachusetts", "Michigan",
+    "Minnesota", "Mississippi", "Missouri", "Montana",
+    "Nebraska", "Nevada", "New Hampshire", "New Jersey",
+    "New Mexico", "New York", "North Carolina", "North Dakota",
+    "Ohio", "Oklahoma", "Oregon",
+    "Pennsylvania", "Rhode Island",
+    "South Carolina", "South Dakota", "Tennessee", "Texas",
+    "Utah", "Vermont", "Virginia",
+    "Washington", "West Virginia", "Wisconsin", "Wyoming"];
+
+function play(states) {
+    console.log(states.length, "states:");
+
+    // get list of unique state names
+    const set = new Set(states);
+
+    // make parallel arrays for unique state names and letter histograms
+    const s = Array.from(set);
+    const h = Array(s.length).fill().map(() => Array(26).fill(0));
+
+    // fill histograms
+    s.forEach((state, i) => {
+        for (const c of state) {
+            const charCode = c.toLowerCase().charCodeAt(0) - 'a'.charCodeAt(0);
+            if (charCode >= 0 && charCode < 26) {
+                h[i][charCode]++;
+            }
+        }
+    });
+
+    // use map to find matches. map key is sum of histograms of
+    // two different states. map value is indexes of the two states.
+    const m = new Map();
+
+    for (let i1 = 0; i1 < h.length; i1++) {
+        const h1 = h[i1];
+        for (let i2 = i1 + 1; i2 < h.length; i2++) {
+            // sum histograms
+            const b = Array(26).fill(0);
+            for (let i = 0; i < 26; i++) {
+                b[i] = h1[i] + h[i2][i];
+            }
+
+            const k = b.join(','); // make key from buffer
+
+            // Check for existing pairs with the same histogram sum
+            if (m.has(k)) {
+                const pairs = m.get(k);
+                // Check each pair against current pair
+                for (const pair of pairs) {
+                    if (i1 !== pair.i1 && i1 !== pair.i2 && i2 !== pair.i1 && i2 !== pair.i2) {
+                        console.log(`${s[i1]}, ${s[i2]} = ${s[pair.i1]}, ${s[pair.i2]}`);
+                    }
+                }
+            } else {
+                m.set(k, []);
+            }
+
+            // store this pair in the map whether printed or not
+            m.get(k).push({ i1, i2 });
+        }
+    }
+}
+
+function main() {
+    play(states);
+    play([...states, "New Kory", "Wen Kory", "York New", "Kory New", "New Kory"]);
+}
+
+main();