Adding Ana's solution.

PKU/2637 - Worst Weather Ever/ana.cpp

@@ -0,0 +1,167 @@
+using namespace std;
+#include <algorithm>
+#include <iostream>
+#include <iterator>
+#include <numeric>
+#include <sstream>
+#include <fstream>
+#include <cassert>
+#include <climits>
+#include <cstdlib>
+#include <cstring>
+#include <string>
+#include <cstdio>
+#include <vector>
+#include <cmath>
+#include <queue>
+#include <deque>
+#include <stack>
+#include <list>
+#include <map>
+#include <set>
+
+#define foreach(x, v) for (typeof (v).begin() x=(v).begin(); x !=(v).end(); ++x)
+#define For(i, a, b) for (int i=(a); i<(b); ++i)
+#define D(x) cout << #x " is " << x << endl
+
+const int MAXN = 50005;
+const int MAXTREE = 1 << 16;
+int a [MAXN];
+int tree [2 * MAXTREE];
+map <int, int> year2int;
+int n;
+
+int query(int u, int l, int r, int p, int q){
+    // printf("Call query u = %d, l = %d, r = %d, p = %d, q = %d\n", u, l, r, p, q);
+    assert (p <= q and l <= r);
+
+    // Node outside the query
+    if (q < l or r < p) return -1;
+
+    // Node totally inside the query
+    if (p <= l and r <= q) return tree[u];
+
+    // Node partiall inside the query
+    int m = (r + l) / 2;
+    int left = query(2 * u + 1, l, m, p, q);
+    int right = query(2 * u + 2, m + 1, r, p, q);
+
+    return max(left, right);
+}
+
+void build(int u, int l, int r){
+    if (l == r){
+        tree[u] = a[l];
+        return;
+    }
+    int m = (l + r) / 2;
+    build(2 * u + 1, l, m);
+    build(2 * u + 2, m + 1, r);
+    tree[u] = max(tree[2 * u + 1], tree[2 * u + 2]);
+}
+
+void solve (int y, int x){
+    assert(y < x);
+
+    // Query outside of known range
+    int fst = (year2int.begin())->first;
+    int lst = (--year2int.end())->first;
+    if (x < fst or y > lst){
+        puts("maybe");
+        return;
+    }
+
+    map <int, int> :: iterator lb, ub, p, q;
+    lb = year2int.lower_bound(y);
+    ub = --year2int.upper_bound(x);
+
+    // No element in the query is in known
+    if(lb->first > ub->first){
+        puts("maybe");
+        return;
+    }
+
+    // All values are known
+    if (lb->first == y and ub->first == x and ub->second - lb->second == x - y){
+        x = year2int[x]; y = year2int[y];
+        if (a[y] < a[x]) {
+            puts("false");
+            return;
+        }
+        int ans = -1;
+        if (y + 1 <= x - 1) ans = query(0, 0, n - 1, y + 1, x - 1);
+        if (a[x] > ans) puts("true");
+        else puts("false");
+        return;
+    }
+
+    // Some values are not known
+
+    p = year2int.lower_bound(y + 1);
+    q = year2int.upper_bound(x - 1);
+    int ans = 0;
+    if (y + 1 <= x - 1 and p != year2int.end() and q != year2int.begin() and p->first <= (--q)->first){
+        // printf("Pregunto por los años: %d, %d\n", p->first, q->first);
+        ans = query(0, 0, n - 1, p->second, q->second);
+    }
+
+    // both y and x are known
+    if (lb->first == y and ub->first == x){
+        //printf("Para y = %d, x = %d entre a x y y conocidos\n", y, x);
+        if (ans < a[year2int[x]] and a[year2int[x]] <= a[year2int[y]]) puts("maybe");
+        else puts("false");
+        return;
+    }
+    // y known but not x
+    if (lb->first == y){
+        // printf("Para y = %d, x = %d entre a y conocido\n", y, x);
+        if (ans < a[year2int[y]] ) puts("maybe");
+        else puts("false");
+        return;
+    }
+    // x known but not y
+    if (ub->first == x){
+        // printf("Para y = %d, x = %d entre a x conocido\n", y, x);
+        if (ans < a[year2int[x]]) puts("maybe");
+        else puts("false");
+    }
+
+    // Neither x nor y known
+    puts("maybe");
+
+}
+
+
+int main(){
+    assert(MAXN <= MAXTREE);
+    bool first = true;
+    while (scanf("%d", &n) == 1){
+        year2int.clear();
+        for (int i = 0; i < n; i++){
+            int y, r; scanf("%d %d", &y, &r);
+            year2int[y] = i;
+            a[i] = r;
+        }
+
+        int m; scanf("%d", &m);
+        if (n == 0 and m == 0) break;
+
+        build(0, 0, n - 1);
+        if (!first) puts("");
+
+        map <int, int> :: iterator it;
+
+        // puts("\nMap has:");
+        // for (it = year2int.begin(); it != year2int.end(); it++){
+        //     printf("%d->%d\n", it->first, it->second);
+        // }
+
+        for (int i = 0; i < m; i++){
+            int y, x; scanf("%d %d", &y, &x);
+            solve(y, x);
+        }  
+        first = false;
+    }
+
+    return 0;
+}

PKU/2637 - Worst Weather Ever/gen.rb

@@ -0,0 +1,23 @@
+10.times do
+  n = 50_000
+  puts n
+
+  previous_year = -10**9
+  n.times do
+    y = previous_year + rand(10000)
+    rain = rand(10**9) + 1
+    puts "#{y} #{rain}"
+
+    previous_year = y
+  end
+
+  m = 10_000
+  puts m
+  m.times do
+    y1 = rand(10**9 + 1) * (rand(2) == 0 ? 1 : -1)
+    y2 = rand(10**9 + 1) * (rand(2) == 0 ? 1 : -1)
+    y1, y2 = y2, y1 if y2 < y1
+    puts "#{y1} #{y2}"
+  end
+end
+puts "0 0"