weekly contest 348

Author: ZLBer

README.md

@@ -4,6 +4,8 @@ Record leetcode contest and ideas every week, and encourage yourself to think mo
 
 leetcode url: <https://leetcode.cn/u/cctest/>
 
+
+* ☀️ [weekly contest 348](src/main/java/weekly/wk348.java)     哈希 | 分类讨论 | 逆向 | 数位DP
 * ☀️ [weekly contest 346](src/main/java/weekly/wk346.java)     栈 | 遍历 | 回溯 | Dijkstra
 * ☀️ [weekly contest 345](src/main/java/weekly/wk345.java)     模拟 | 异或 | dp | 并查集
 * ☀️ [weekly contest 344](src/main/java/weekly/wk344.java)     前缀和 | 哈希 | 模拟 | 树形dp

src/main/java/weekly/wk348.java

@@ -0,0 +1,100 @@
+package weekly;
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+public class wk348 {
+
+
+    //哈希
+    public int minimizedStringLength(String s) {
+        Set<Character> set = new HashSet<>();
+        for (int i = 0; i < s.length(); i++) {
+            set.add(s.charAt(i));
+        }
+        return set.size();
+    }
+
+
+    //分类讨论吧
+    public int semiOrderedPermutation(int[] nums) {
+        int min = 0, max = 0;
+        for (int i = 0; i < nums.length; i++) {
+            if (nums[i] == 1) {
+                min = i;
+            } else if (nums[i] == nums.length) {
+                max = i;
+            }
+        }
+        int ans = min - 1 + nums.length - max;
+        if (max < min) {
+            ans--;
+        }
+        return ans;
+    }
+
+
+    //逆着遍历，然后乘法快速计算
+    static public long matrixSumQueries(int n, int[][] queries) {
+        long ans = 0;
+
+        Set<Integer> row = new HashSet<>();
+        Set<Integer> col = new HashSet<>();
+        for (int i = queries.length - 1; i >= 0; i--) {
+            int[] query = queries[i];
+            if (query[0] == 0) {
+                if (row.contains(query[1])) continue;
+                ans += ((long) n - col.size()) * (long) query[2];
+                row.add(query[1]);
+            } else {
+                if (col.contains(query[1])) continue;
+                ans += ((long) n - row.size()) * (long) query[2];
+                col.add(query[1]);
+            }
+        }
+
+        return ans;
+    }
+
+
+    //数位dp
+    int mod=(int)1e9+7;
+    public int count(String num1, String num2, int minSum, int maxSum) {
+        int ans = count(num2,maxSum,minSum) - count(num1,maxSum,minSum) + mod; // 避免负数
+        int sum = 0;
+        for (char c : num1.toCharArray()) sum += c - '0';
+        if (minSum <= sum && sum <= maxSum) ans++; // x=num1 是合法的，补回来
+        return ans % mod;
+    }
+
+    private int count(String S, int maxSum,int minSum) {
+        char[] s = S.toCharArray();
+        int n = s.length;
+        int [][] memo = new int[n][Math.min(9 * n, maxSum) + 1];
+        for (int i = 0; i < n; i++)
+            Arrays.fill(memo[i], -1); // -1 表示没有计算过
+        return f(s, memo, 0, 0, true,maxSum,minSum);
+    }
+
+    private int f(char[] s, int[][] memo, int i, int sum, boolean isLimit, int maxSum,int minSum) {
+        if (sum > maxSum) return 0;
+        if (i >= s.length) return sum>=minSum?1:0;
+        if (isLimit && memo[i][sum] != -1) return memo[i][sum];
+
+        int up = isLimit ? s[i] - '0' : 9;
+        int res=0;
+        for (int u = 0; u <= up; u++) {
+           res+=f(s,memo,i+1,sum+u,isLimit&&u==up,maxSum,minSum);
+           res%=mod;
+        }
+       if(!isLimit) memo[i][sum]=res;
+       return res;
+    }
+
+    public static void main(String[] args) {
+
+    }
+
+
+}