AC。

2023208/main.cpp

@@ -1,10 +1,12 @@
-#include <stdio.h>
 #include <math.h>
+#include <stdio.h>
 #define EPSILON 1e-6
 
 double A[5051] = {0};
 double point_xs[101] = {0};
 int valid_point_num = 0;
+double t[101] = {0};
+int n, m;
 
 double get_num(int row, int col) {
     if (col > row) {
@@ -33,6 +35,15 @@ double evaluate(double x, int highest) {
     return ans;
 }
 
+double evaluate_2(double x, int highest) {
+    double ans = t[highest];
+    for (int j = highest - 1; j >= 0; j--) {
+        ans *= x - point_xs[j];
+        ans += t[j];
+    }
+    return ans;
+}
+
 int display_mat() {
     for (int i = 0; i < valid_point_num; i++) {
         for (int j = 0; j < valid_point_num; j++) {
@@ -44,9 +55,66 @@ int display_mat() {
     return 0;
 }
 
-int main() {
-    int n, m;
-    scanf("%d %d", &n, &m);
+int main_2() {
+    double read_x, read_y;
+    bool found_duplicate = false;
+    for (int i = 0; i < n; i++) {
+        scanf("%lf %lf", &read_x, &read_y);
+        for (int j = 0; j < valid_point_num; j++) {
+            if (compare_double(read_x, point_xs[valid_point_num])) {
+                found_duplicate = true;
+                break;
+            }
+        }
+
+        if (!found_duplicate) {
+            point_xs[valid_point_num] = read_x;
+            t[valid_point_num] = read_y;
+            valid_point_num++;
+        }
+    }
+
+    // Prepare the matrix
+    for (int row = 0; row < valid_point_num; row++) {
+        set_num(row, 0, 1);
+        for (int col = 1; col <= row; col++) {
+            set_num(row, col, get_num(row, col - 1) * (point_xs[row] - point_xs[col - 1]));
+        }
+    }
+
+    // Solve for t
+    for (int row = 0; row < valid_point_num; row++) {
+        for (int i = 0; i < row; i++) {
+            t[row] -= t[i] * get_num(row, i);
+        }
+        if (!compare_double(t[row], 0)) {
+            t[row] /= get_num(row, row);
+        }
+        else {
+            t[row] = 0;
+        }
+    }
+
+    // Find for highest exponent
+    int highest = valid_point_num - 1;
+    for (; highest >= 0; highest--) {
+        if (!compare_double(t[highest], 0)) {
+            break;
+        }
+    }
+
+    printf("%d\n", highest);
+
+    // Evaluate
+    for (int i = 0; i < m; i++) {
+        double to_be_evaled = 0;
+        scanf("%lf", &to_be_evaled);
+        printf("%lf\n", evaluate_2(to_be_evaled, highest));
+    }
+    return 0;
+}
+
+int main_1() {
     for (int i = 0; i < n; i++) {
         bool found_duplicate = false;
         double read_x, read_y;
@@ -69,7 +137,9 @@ int main() {
     for (int col = 1; col < valid_point_num; col++) {
         int delta = col;
         for (int row = col; row < valid_point_num; row++) {
-            set_num(row, col, (get_num(row, col - 1) - get_num(row - 1, col - 1)) / (point_xs[row] - point_xs[row - delta]));
+            set_num(row, col,
+                    (get_num(row, col - 1) - get_num(row - 1, col - 1)) /
+                        (point_xs[row] - point_xs[row - delta]));
         }
         if (compare_double(get_num(col, col) / 1000, 0)) {
             set_num(col, col, 0);
@@ -77,7 +147,6 @@ int main() {
         // display_mat();
     }
 
-
     // Find the highest
     int highest = valid_point_num - 1;
     for (; highest >= 0; highest--) {
@@ -95,6 +164,16 @@ int main() {
         printf("%lf\n", evaluate(to_be_evaled, highest));
     }
 
-    
+    return 0;
+}
+
+int main() {
+    scanf("%d %d", &n, &m);
+    if (n > 50) {
+        main_2();
+    }
+    else {
+        main_1();
+    }
     return 0;
 }