diff --git a/2021/0/bullets.c b/2021/0/bullets.c
new file mode 100644
index 0000000..36b78be
--- /dev/null
+++ b/2021/0/bullets.c
@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+typedef struct {
+    int value, pos;
+} Node;
+
+void selectionSort(Node * sequence, int size) {
+    int i, j, pos;
+    Node aux;
+
+    for (i = 0; i < size - 1; i++) {
+        pos = i;
+        for (j = i + 1; j < size; j++)
+            if (sequence[j].value < sequence[pos].value)
+                pos = j;
+        aux = sequence[i];
+        sequence[i] = sequence[pos];
+        sequence[pos] = aux;
+    }
+}
+
+int main(){
+    int n, i, size, value;
+    Node * array;
+
+    scanf("%d\n%d", &n, &size);
+    while (n > 0) {
+        array = malloc(size * sizeof(*array));
+        for (i = 0; i < size; i++) {
+            array[i].pos = i;
+            scanf("%d", &value);
+            array[i].value = value;
+        }
+        selectionSort(array, size);
+        for (i = 0; i < size; i++)
+            printf("%d-%d ", array[i].value, array[i].pos);
+        printf("\n");
+        free(array);
+        n--;
+    }
+    return 0;
+}
diff --git a/2021/0/desafio1.pdf b/2021/0/desafio1.pdf
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diff --git a/2021/0/desafio2.pdf b/2021/0/desafio2.pdf
new file mode 100644
index 0000000..2515c5c
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diff --git a/2021/0/desafio3.pdf b/2021/0/desafio3.pdf
new file mode 100644
index 0000000..b1378d2
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diff --git a/2021/0/desafio4.pdf b/2021/0/desafio4.pdf
new file mode 100644
index 0000000..6a6240d
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diff --git a/2021/0/hash.out b/2021/0/hash.out
new file mode 100755
index 0000000..d897044
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diff --git a/2021/0/mensagem.c b/2021/0/mensagem.c
new file mode 100644
index 0000000..3b08d9e
--- /dev/null
+++ b/2021/0/mensagem.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <string.h>
+
+int main(){
+    int n;
+    char c1, c2, output;
+
+    for(scanf("%d\n", &n); n > 0; n--) {
+        while (scanf("%c", &c1) && c1 != '\n') {
+            if (c1 == ' ') {
+                printf(" ");
+                continue;
+            }
+            scanf("%c", &c2);
+            output = 'A' + 5 * (c1 - '0') + (c2 - '0');
+            if (output <= 'Z'){
+                printf("%c", output);
+                continue;
+            }
+            switch (output) {
+                case 'Z' + 1:
+                    printf(",");
+                    break;
+                case 'Z' + 2:
+                    printf(".");
+                    break;
+                case 'Z' + 3:
+                    printf("?");
+                    break;
+                default:
+                    printf("!");
+            }
+        }
+        printf("\n");
+    }
+    return 0;
+}
diff --git a/2021/0/ninja.c b/2021/0/ninja.c
new file mode 100644
index 0000000..776c443
--- /dev/null
+++ b/2021/0/ninja.c
@@ -0,0 +1,32 @@
+#include <stdio.h>
+
+int main () {
+    int n = 0;
+    char c;
+
+    for (scanf("%d\n", &n); n > 0; n--) {
+        while (scanf("%c", &c) && c != '\n') {
+            switch (c) {
+                case 'D':
+                    printf("Rolada tatica ninja.\n");
+                    break;
+                case 'E':
+                    printf("Esquerdei, e agora?\n");
+                    break;
+                case 'C':
+                    printf("Eita pipoco. Zumm!\n");
+                    break;
+                case 'B':
+                    printf("\n");
+                    break;
+                case 'F':
+                    printf("Pronto e agora, e agora?\n");
+                    break;
+                case 'A':
+                    printf("Nem ferrando. Vou de agentes mesmo.\n");
+                    break;
+            }
+        }
+    }
+    return 0;
+}
diff --git a/2021/0/ninja.out b/2021/0/ninja.out
new file mode 100755
index 0000000..61d5a4f
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diff --git a/2021/0/tic_tac.c b/2021/0/tic_tac.c
new file mode 100644
index 0000000..30eb1ca
--- /dev/null
+++ b/2021/0/tic_tac.c
@@ -0,0 +1,101 @@
+#include <stdio.h>
+
+int resolve (char game[3][3], int * line) {
+    int i, j;
+    char win = 'O';
+
+    for (i = 1; i < 3; i++) {
+
+        /* Teste horizontal */
+        for (j = 0; j < 9; j++) {
+            if (game[j / 3][j % 3] != win)
+                j += 2 - (j % 3);
+            else if (j % 3 == 2) {
+                if (win == 'V') {
+                    j -= 2;
+                    do {
+                        line[j % 3] = 10 * (j / 3) + (j % 3) + 11;
+                        game[j / 3][j % 3] = 'X';
+                        j++;
+                    } while(j % 3 != 0);
+                }
+                return i;
+            }
+        }
+
+        /* Teste vertical */
+        for (j = 0; j < 9; j++) {
+            if (game[j % 3][j / 3] != win)
+                j += 2 - (j % 3);
+            else if (j % 3 == 2) {
+                if (win == 'V') {
+                    j -= 2;
+                    do {
+                        line[j % 3] = 10 * (j % 3) + (j / 3) + 11;
+                        game[j % 3][j / 3] = 'X';
+                        j++;
+                    } while(j % 3 != 0);
+                }
+                return i;
+            }
+        }
+
+        /* Caso diagonal direto */
+        for (j = 0; j < 3; j++) {
+            if (game[j][j] != win)
+                break;
+            if (j == 2) {
+                if (win == 'V') {
+                    for (j = 0; j < 3; j++) {
+                        line[j] = 11 * j + 11;
+                        game[j][j] = 'X';
+                    }
+                }
+                return i;
+            }
+        }
+
+        /* Caso diagonal inverso */
+        for (j = 0; j < 3; j++) {
+            if (game[2 - j][j] != win)
+                break;
+            if (j == 2) {
+                if (win == 'V') {
+                    for (j = 0; j < 3; j++) {
+                        line[2 - j] = 10 * (2 - j) + j + 11;
+                        game[2 - j][j] = 'X';
+                    }
+                }
+                return i;
+            }
+        }
+        win = 'V';
+    }
+    return 0;
+}
+
+int main () {
+    int i, line[3], n = 0;
+    char game[3][3];
+
+    for (scanf("%d", &n); n > 0; n--) {
+        for (i = 0; i < 9; i++)
+            scanf(" %c", &game[i / 3][i % 3]);
+        switch (resolve(game, line)) {
+            case 0:
+                printf("Bora outra valendo os dois Tic-Tac ?\n");
+                break;
+            case 1:
+                printf("Tic-Tac de cereja eh bom tambem\n");
+                break;
+            default:
+                printf("Hora de tirar o bafo\n%d-%d-%d\n", line[0], line[1], line[2]);
+                for (i = 0; i < 9; i++) {
+                    printf("%c ", game[i / 3][i % 3]);
+                    if (i % 3 == 2)
+                        printf("\n");
+                }
+        }
+    }
+    return 0;
+}