#1847. [COCI2017-2018#7] Go

https://sjzezoj.com/submission/69942

S2OJ/1847/1847.cpp

@@ -0,0 +1,84 @@
+#include <iostream>
+#include <algorithm>
+#include <cmath>
+#include <cstring>
+#include <iterator>
+
+using std::cin;
+using std::cout;
+const char endl = '\n';
+
+const int N = 2005,
+          M = 105;
+
+int n, k, m, a[M], b[M], t[M], max, ans;
+// 访问过最左端的房子为 l
+//      最右端的房子为 r
+// 时间已经过了 k 秒
+// 目前正在 左(0) / 右(1) 端
+int f[M][M][N][2];
+
+int main() {
+    std::ios::sync_with_stdio(false);
+    cin.tie(nullptr);
+
+    memset(f, 0xc0, sizeof(f));
+
+    cin >> n >> k >> m;
+
+    for (int i = 1; i <= m; i++) {
+        cin >> a[i] >> b[i] >> t[i];
+
+        max = std::max(max, t[i]);
+    }
+
+    int x = std::distance(a, std::lower_bound(a + 1, a + 1 + m, k)),
+        y = std::distance(a, std::upper_bound(a + 1, a + 1 + m, k)) - 1;
+
+    if (a[x] == k) {
+        f[x][x][0][0]
+            = f[x][x][0][1]
+            = (std::abs(a[x] - k) < t[x]) * b[x];
+    } else {  // 起始点没有宝可梦
+        f[x][x][std::abs(a[x] - k)][0]
+            = f[x][x][std::abs(a[x] - k)][1]
+            = (std::abs(a[x] - k) < t[x]) * b[x];
+        f[y][y][std::abs(a[y] - k)][0]
+            = f[y][y][std::abs(a[y] - k)][1]
+            = (std::abs(a[y] - k) < t[y]) * b[y];
+    }
+
+    for (int len = 2; len <= m; len++) {
+        for (int l = 1, r = l + len - 1; r <= m; l++, r++) {
+            for (int k = a[r] - a[l]; k <= max; k++) {
+                f[l][r][k][0] = std::max({
+                    f[l][r][k][0],
+                    f[l + 1][r][k - (a[l + 1] - a[l])][0] + (k < t[l]) * b[l],
+                    f[l + 1][r][k - (a[r] - a[l])][1] + (k < t[l]) * b[l],
+                });
+
+                f[l][r][k][1] = std::max({
+                    f[l][r][k][1],
+                    f[l][r - 1][k - (a[r] - a[r - 1])][1] + (k < t[r]) * b[r],
+                    f[l][r - 1][k - (a[r] - a[l])][0] + (k < t[r]) * b[r],
+                });
+            }
+        }
+    }
+
+    for (int l = 1; l <= m; l++) {
+        for (int r = l; r <= m; r++) {
+            for (int k = 0; k <= max; k++) {
+                ans = std::max({
+                    ans,
+                    f[l][r][k][0],
+                    f[l][r][k][1],
+                });
+            }
+        }
+    }
+
+    cout << ans << endl;
+
+    return 0;
+}