Create 1395.统计作战单位数.js

Author: yinxin630

1395.统计作战单位数.js

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+/**
+ * @param {number[]} rating
+ * @return {number}
+ */
+var numTeams = function(rating) {
+    if (rating < 3) {
+        return 0;
+    }
+    let dp1 = new Array(3);
+    for (let i = 0; i < 3; i++) {
+        dp1[i] = [];
+        for (let j = 0; j < rating.length; j++) {
+            if (i === 0) {
+                dp1[i][j] = 1;
+            } else {
+                dp1[i][j] = 0;
+                for (let k = 0; k < j; k++) {
+                    if (rating[j] > rating[k]) {
+                        dp1[i][j] += dp1[i - 1][k];
+                    }
+                }
+            }
+        }
+    }
+
+    let dp2 = new Array(3);
+    for (let i = 0; i < 3; i++) {
+        dp2[i] = [];
+        for (let j = 0; j < rating.length; j++) {
+            if (i === 0) {
+                dp2[i][j] = 1;
+            } else {
+                dp2[i][j] = 0;
+                for (let k = 0; k < j; k++) {
+                    if (rating[j] < rating[k]) {
+                        dp2[i][j] += dp2[i - 1][k];
+                    }
+                }
+            }
+        }
+    }
+
+    let result = 0;
+    for (let i = 0; i < rating.length; i++) {
+        result += dp1[2][i] + dp2[2][i];
+    }
+    return result;
+};