[2sem] pb19 done

2sem/programming basics/19/100.cpp

@@ -0,0 +1,128 @@
+// pb_19_100.cpp
+// Горбацевич Андрей
+#include <iostream>
+#include <set>
+#include <vector>
+#include <string>
+
+using namespace std;
+
+struct point {
+    int x,y;
+};
+struct field {
+    int field[8][8] = {};
+};
+
+void print_mtx(field&);
+void traverse(point at, field&);
+void draw_shortest(point at, field&);
+
+auto comparePoints = [](const point &a, const point &b)
+{
+    return (a.x < b.x) || (a.y < b.y);
+};
+set<point, decltype(comparePoints)> visited;
+
+char i2f(int p) {
+    if (p < 0 || p > 8) {
+        throw out_of_range("char should be in a..h");
+    }
+    return char(int('a') + p);
+}
+int f2i(char _c) {
+    char c = char(tolower(_c));
+    if (c < 'a' || c > 'h') {
+        throw out_of_range("char should be in a..h");
+    }
+    return (c % 'a');
+}
+
+bool pif(point p) {
+    return ((p.x < 8) && (p.x >= 0)) && ((p.y < 8) && (p.y >= 0));
+}
+
+int main() {
+    cout << "Enter starting point (e.g. c3) >>>";
+    point pos{};
+    char xe;
+    cin >> xe;
+    pos.x = f2i(xe);
+    cin >> pos.y;
+    pos.y -= 1;
+    if (pos.y < 0 || pos.y >= 8) {
+        throw out_of_range("y pos should be in 1..8");
+    }
+
+    cout << "Enter end point (e.g. c3) >>>";
+    point end{};
+    cin >> xe;
+    end.x = f2i(xe);
+    cin >> end.y;
+    end.y -= 1;
+    if (end.y < 0 || end.y >= 8) {
+        throw out_of_range("y pos should be in 1..8");
+    }
+
+    field f;
+    f.field[pos.x][pos.y] = 1;
+    //print_mtx(f);
+    traverse(pos, f);
+    //print_mtx(f);
+    cout << "It takes " << f.field[end.x][end.y] << " steps to get here (inc. first pos.)." << endl;
+    cout << "Possible route: ";
+    draw_shortest(end, f);
+    cout << i2f(end.x) << end.y+1;
+
+    return 0;
+}
+
+void print_mtx(field &f) {
+    for (int i = 0; i < 8; i++) {
+        for (int j = 0; j < 8; j++) {
+            cout << f.field[i][j] << " ";
+        }
+        cout << endl;
+    }
+    cout << endl;
+}
+
+void traverse(point at, field &f) {
+    vector<point> pts = {
+            {at.x+1, at.y-2}, {at.x+2, at.y-1},
+            {at.x+2, at.y+1}, {at.x+1, at.y+2},
+            {at.x-1, at.y+2}, {at.x-2, at.y+1},
+            {at.x-2, at.y-1}, {at.x-1, at.y-2},
+    };
+
+    for (auto pt : pts) {
+        if (!pif(pt) || f.field[pt.x][pt.y] != 0) {
+            continue;
+        }
+        f.field[pt.x][pt.y] = f.field[at.x][at.y] + 1;
+    }
+    for (auto pt : pts) {
+        if (!pif(pt) || f.field[pt.x][pt.y] != f.field[at.x][at.y]+1) {
+            continue;
+        }
+        traverse(pt, f);
+    }
+}
+
+void draw_shortest(point at, field &f) {
+    vector<point> pts = {
+            {at.x+1, at.y-2}, {at.x+2, at.y-1},
+            {at.x+2, at.y+1}, {at.x+1, at.y+2},
+            {at.x-1, at.y+2}, {at.x-2, at.y+1},
+            {at.x-2, at.y-1}, {at.x-1, at.y-2},
+    };
+
+    for (auto pt : pts) {
+        if (!pif(pt) || f.field[pt.x][pt.y] != f.field[at.x][at.y]-1) {
+            continue;
+        }
+        draw_shortest(pt, f);
+        cout << i2f(pt.x) << pt.y+1 << " -> ";
+        break;
+    }
+}