weekly contest 399

Author: ZLBer

README.md

@@ -3,7 +3,9 @@
 Record leetcode contest and ideas every week, and encourage yourself to think more.
 
 leetcode url: <https://leetcode.cn/u/cctest/>
-* 🐼 [weekly contest 398](src/main/java/weekly/wk398.java)     遍历 | 前缀和 | 遍历 |记忆化搜索/组合数
+
+* 🐼 [weekly contest 399](src/main/java/weekly/wk399.java)     哈希 | 遍历 | 哈希 | 线段树
+* 🐼 [weekly contest 398](src/main/java/weekly/wk398.java)     遍历 | 前缀和 | 遍历 | 记忆化搜索/组合数
 * 🐼 [weekly contest 397](src/main/java/weekly/wk397.java)     哈希 | 遍历 | dp |记忆化搜索
 * 🐼 [weekly contest 394](src/main/java/weekly/wk394.java)     遍历 | 遍历 | 记忆化搜索 | Dijkstra
 * 🐼 [weekly contest 393](src/main/java/weekly/wk393.java)     枚举 | 遍历 | 二分 | dp

src/main/java/weekly/wk399.java

@@ -0,0 +1,144 @@
+package weekly;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+public class wk399 {
+//    public int numberOfPairs(int[] nums1, int[] nums2, int k) {
+//
+//    }
+
+
+    // 遍历
+    public String compressedString(String word) {
+        char pre = word.charAt(0);
+        int count = 1;
+        StringBuilder sb = new StringBuilder();
+        for (int i = 1; i < word.length(); i++) {
+            char c = word.charAt(i);
+            if (c != pre || count == 9) {
+                sb.append(count);
+                sb.append(pre);
+                pre = c;
+                count = 1;
+            } else {
+                count++;
+            }
+        }
+        sb.append(count);
+        sb.append(pre);
+        return sb.toString();
+    }
+
+
+    //
+    public long numberOfPairs(int[] nums1, int[] nums2, int k) {
+        int max = 0;
+        Map<Integer, Integer> map = new HashMap<>();
+        for (int i : nums1) {
+            max = Math.max(i, max);
+            map.put(i, map.getOrDefault(i, 0) + 1);
+        }
+        Map<Integer, Integer> map1 = new HashMap<>();
+        for (int i : nums2) {
+            map1.put(i * k, map1.getOrDefault(i * k, 0) + 1);
+        }
+
+        long ans = 0;
+        for (Map.Entry<Integer, Integer> entry : map1.entrySet()) {
+            int num = entry.getKey();
+            int count = entry.getValue();
+            for (int i = 1; i * num <= max; i++) {
+                if (map.containsKey(i * num)) {
+                    ans += ((long) map.get(i * num)) * count;
+                }
+            }
+        }
+        return ans;
+    }
+
+
+    static final int MOD = 1000000007;
+
+    //线段树
+    public int maximumSumSubsequence(int[] nums, int[][] queries) {
+        int n = nums.length;
+        SegTree tree = new SegTree(nums);
+        long sum = 0;
+        for (int[] q : queries) {
+            tree.update(q[0], q[1]);
+            sum = (sum + tree.query()) % MOD;
+        }
+        return (int) sum;
+    }
+
+    public class SegTree {
+        long[] max;// 最优子序列和
+        long[] pre;// 不包含右端点最优子序列和
+        long[] suf;// 不包含左端点最优子序列和
+        long[] not;// 既不包含左端点又不包含右端点最优子序列和
+        int N;
+
+        public SegTree(int[] nums) {
+            N = nums.length;
+            max = new long[N << 2];
+            pre = new long[N << 2];
+            suf = new long[N << 2];
+            not = new long[N << 2];
+            build(nums, 1, N, 1);
+        }
+
+        // 初始化
+        private void build(int[] nums, int l, int r, int i) {
+            if (l == r) {
+                max[i] = Math.max(nums[l - 1], 0);
+                return;
+            }
+            int m = (l + r) >> 1;
+            build(nums, l, m, i << 1);
+            build(nums, m + 1, r, i << 1 | 1);
+            up(i);
+        }
+
+        // 区间合并
+        private void up(int i) {
+            int l = i << 1, r = i << 1 | 1;
+            max[i] = Math.max(pre[l] + max[r], max[l] + suf[r]);
+            pre[i] = Math.max(max[l] + not[r], pre[l] + pre[r]);
+            suf[i] = Math.max(not[l] + max[r], suf[l] + suf[r]);
+            not[i] = Math.max(suf[l] + not[r], not[l] + pre[r]);
+        }
+
+        // 单点更新
+        public void update(int index, int value) {
+            update(index + 1, value, 1, N, 1);
+        }
+
+        private void update(int idx, int v, int l, int r, int i) {
+            if (l == r) {
+                max[i] = Math.max(v, 0);
+                return;
+            }
+            int m = (l + r) >> 1;
+            if (idx <= m) {
+                update(idx, v, l, m, i << 1);
+            } else {
+                update(idx, v, m + 1, r, i << 1 | 1);
+            }
+            up(i);
+        }
+
+        // 1 代表区间 [0, n - 1]
+        public long query() {
+            return max[1];
+        }
+    }
+
+
+    public static void main(String[] args) {
+    }
+
+}